Hey all. Forum newbie here looking for a little advice!

I’ve not played pen and paper D&D since school, and have just started up again with a couple of old schoolmates. In the interests of making up numbers, our DM Steve invited his cousin Lloyd to join our group. 

Since we started the campaign. It’s become quite clear that Lloyd is a D&D expert. He routinely corrects Steve over minutiae, or jumps in to answer questions that the other players ask Steve before Steve himself has a chance to respond. I understand that he's a couple of years younger than us and that this is likely just enthusiasm, but sometimes it can feel overbearing. In our most recent session Lloyd started telling us how to make best to use our actions when our turns rolled around...

Eventually our party reached a promising looking treasure room. A large chest encircled by several stone tombs. My Chaotic Good thief was readying himself to scour the room for traps, when Lloyd’s pious Paladin interrupted to announce that “no one was to disturb the tomb!”. When I was about to ask why, he spoke over me and announced “grave-robbing is *morally wrong!*“ I would have argued, but Lloyd’s our DM’s cousin and our guest, so I decided not to.

Now, I understand that Paladins are prone to being dogmatic and pious, but I’ve never met one who was such a control freak before, and I’m trying to establish the best response for my thief to make. Should I sneak back to the tomb next rest and rob it in secret? Or as the group’s principal loot mule, I might just give him a smaller share of the remaining treasure. A paladin’s morals involve sacrifice, but if we can’t smite people, then I see no reason why our bottom line should be impacted by his dogma. What do you guys think?

Quote from AranLinvail >>

Since we started the campaign. It’s become quite clear that Lloyd is a D&D expert. He routinely corrects Steve over minutiae, or jumps in to answer questions that the other players ask Steve before Steve himself has a chance to respond.

 
This is up to Steve. If he's fine with it, then there's nothing wrong. I can be a little like this with my DM, I'll message him privately if I think he might have forgotten something - I'm more familiar with rules than him, but I have discussed this with him and he appreciates it. I don't argue anything, I just remind, he can change things as he needs as a DM. Lloyd might just be doing this, albeit publically, and Steve might even be appreciative. It's up to him.

Quote from AranLinvail >>

 In our most recent session Lloyd started telling us how to make best to use our actions when our turns rolled around...

 
It seems like he's trying to be helpful but if you personally find it annoying simply tell him you appreciate him wanting to help but you would prefer he did not do this. Might be best to do this in private conversation rather than at the table.

Quote from AranLinvail >>

Eventually our party reached a promising looking treasure room. A large chest encircled by several stone tombs. My Chaotic Good thief was readying himself to scour the room for traps, when Lloyd’s pious Paladin interrupted to announce that “no one was to disturb the tomb!”. When I was about to ask why, he spoke over me and announced “grave-robbing is *morally wrong!*“ I would have argued, but Lloyd’s our DM’s cousin and our guest, so I decided not to.

Now, I understand that Paladins are prone to being dogmatic and pious, but I’ve never met one who was such a control freak before, and I’m trying to establish the best response for my thief to make. Should I sneak back to the tomb next rest and rob it in secret? Or as the group’s principal loot mule, I might just give him a smaller share of the remaining treasure. A paladin’s morals involve sacrifice, but if we can’t smite people, then I see no reason why our bottom line should be impacted by his dogma. What do you guys think?

 
It is more likely just how he feels he should be roleplaying his character. There's nothing wrong with that. Respecting the dead and their possessions is a common custom, since technically taking from the dead without inheritance is grave-robbing and illegal in most places and likely in the campaign's world. It does make sense for somebody who values the law and so on to not want the dead to be violated in such way (or any way). This is more of being a lawful / good alignment rather than a paladin. It's not about smiting it's about respecting people, even after they died. The instance you're describing isn't showing a control freak, just a common reaction from any LG/similar character.

Now, should your character listen just because the player is the DM's cousin? Heck No! He could be present or prime minister or a king. At the table he's just a player, the same as you. If your character doesn't care about the dead and would be inclined to take the gold - then your character should take the gold!. You're not doing anything out of bounds or disruptive or stealing from the party or anything. So, go for it! Should also make for some interesting RP moments if the pally does find out.

Cyb3rM1nd, many thanks for this extensive and considered response! Exploring this problem has been very cathartic for me and I'm grateful for your time, especially as a first-time poster!

I'd concur that alignment roleplay is the most probable reason for the behaviour, though I'll struggle to reconcile the shortsightedness of  safeguarding the integrity of a tomb after happily slaughtering the curators; it's just desecration with more steps.

I'm starting to appreciate that what I've labeled control freak behaviour is likely the result of a confident, experienced player running circles around a fairly inexperienced DM. When meeting NPCs, Lloyd interjects before anyone else. (If other PCs speak, he simply speaks over them). His interactions with NPCs can mean other players have zero contribution to the narrative for up to 15 minutes at a time, and our fighter has confirmed he's bored and won't rejoin the party once this quest is concluded.

I'll give some consideration for how best to roleplay a response, but once again, thanks for your feedback, it's really appreciated!

Quote from AranLinvail >>

Eventually our party reached a promising looking treasure room. A large chest encircled by several stone tombs. My Chaotic Good thief was readying himself to scour the room for traps, when Lloyd’s pious Paladin interrupted to announce that “no one was to disturb the tomb!”. When I was about to ask why, he spoke over me and announced “grave-robbing is *morally wrong!*“ I would have argued, but Lloyd’s our DM’s cousin and our guest, so I decided not to.

Now, I understand that Paladins are prone to being dogmatic and pious, but I’ve never met one who was such a control freak before, and I’m trying to establish the best response for my thief to make. Should I sneak back to the tomb next rest and rob it in secret? Or as the group’s principal loot mule, I might just give him a smaller share of the remaining treasure. A paladin’s morals involve sacrifice, but if we can’t smite people, then I see no reason why our bottom line should be impacted by his dogma. What do you guys think?

 
One of the PC's that I'm playing right now would agree with him and sneak back later to loot the tomb without having to split the treasure with him.  The other one doesn't care about wealth so he wouldn't bother with going back to loot the tomb later, but that's because he doesn't care about material goods.  Neither one of them is a rogue.

So, my answer to that question is, what would your rogue do?  What is his personality?

Do the same to him. Give him a taste of his own medicine.

I think it is better to be honest with him and point out that he needs to let others have a chance at talking to NPCs.  Likewise, if one of our paladins said we couldn't loot the treasure, I know what our rogue would do, and he be smiling a smile a mile wide too; You mean this is ALL FOR ME!!!  while he decides how he will create an excuse to come back when the Pali isn't lookin'