I think it could be an interesting sub question of “how much agency (choice) are you willing to give up?  And how often?” Like I 100% agree that an NPC slipping a ring of mind control on you, and then the DM pilots your character as they see fit, is BS.  But I also think that no one is going to actually manage to go through an entire campaign without getting hit with a status ailment that limits your choices to some degree.

Even the most minor status effect can ruin a game if it’s always active/ can be triggered by any/every one

Very early on in D& D you learn that you are not the only capable of changing a foe’s status and that yours can and eventually will. You also learn that there are things you can do to limit the likelyhood and or duration of such effects. However, if a DM decides that you are not playing that effect appropriately and changes the rules to enforce their opinion of how you should play your character it’s time to leave that game. If I he DM wants to talk to me and explain his problems I’m more than happy to listen and is cuss his complaints. If I agree I’m happy to make changes, if I’m not willing and his response is the rule changes then I’ll be moving on and so should all of us in my opinion. The question of how much agency and for how long you are willing to lose is a session zero question that should be raised. Changing the rules to make your own job harder to force players to meet your ideas of how to play strikes me as counter productive. Coming here to talk it over is productive even if your not hearing what you would like to.

I have been part of 2 parties that wiped because the tanks / fighters could not make their saves all night and missed constantly with ranged weapons.  The moment the tank failed the save the cleric became the target and the rest fell like domino's.   One of the 2 parties a had new player that just said to hell with it, and never played again.    The fighter was pined in the corner of the map for about an hour and had no place to move other then to leave the battle by leaving the map and failed every save.    He had visions in his head of Aragorn and basically lost all interest because his character ended up nothing more than a coward due to the dice rolls.   He was the one who lost all interest in the game due to his bad experience on his 2nd time playing.    The sad part is he was excited about it to the point that he wrote like 10 pages for the characters history and the toon was dead on his 2nd time playing him.

I was pissed at the DM for driving him away from the game permanently and never joined any of that DM's pickup games again myself because he cared more about the rules then getting the new players hooked on the game with a good experience.

Sorry to hear about your experience. It sounds like everyone messed up in that situation. No bless?, no guidance? No inspiration? And the DM seems to have the DC set too high if folks are constantly failing.

D&D isn’t like other RPGs, it’s designed differently. Roles like “Tank” don’t necessarily fit this game. For example, there’s no Agro to speak of in D&D, there’s nothing to make anything target specific PCs over and over other than proximity and damage output. So it’s to be expected that the intelligent enemies will target the squishiest, most opportune PCs instead of the great big meat shields. Similarly, not every encounter is “winnable” through combat, at least not without some planning. Did it ever occur to anyone in the party to retreat and regroup, thereby resetting the conditions on the fighter?

If It were me I would try to coax those new players back to the game with an explanation of alternative tactics and strategies, and see if you can’t find a DM that’s better suited to new players. As you’ve noticed, not all DMs are suited to newer players.

I’ll wrap up with a brief anecdote. Thirty years ago I was 10 minutes into my very first session of D&D and my character’s right hand was bitten off at the wrist. I had made an archer, so my character was effectively useless. That’s okay. That stuff happens. That’s when we write up a new character and give it another try. Thirty years later and I’m still playing this wonderful game. If I could continue to find joy in D&D despite my first experience, hopefully your friend can too.

My paladin/ weapons master is a great aggro magnet.  Between the goading attack from battle master and the Paladins ability to compel a dual he makes for a good tank.   Beyond that I do agree with much of what you said.  sadly my buddy lost all interest in the game due to the length of time he dealt with nothing but frustration and let down.   In the end it was the DM that was the problem but the mechanics allowed him to do what he did without concern for the new players.   He could not even move behind cover because he was literally stuck on the edge of the map close to a corner and has no where he could go to get out of line of site.   A bless spell would have helped but if my memory serves there were not many spell slots left by the time that battle occurred. And no, I was not playing my Paladin that night sadly.   Since that night I have felt that the fear mechanic is unbalanced or perhaps the save might be a point or two too high.    But I also do not like E5 as much as some of the older versions.   My favorite rule set is still the original AD&D rules.

If i remember correctly the casters were down to their last spell slots by the time that battle occurred.   And you touched on what i think was the core of the problem.   I feel the save necessary was a point or 2 too high.  especially for a group with new players.

In that situation he should have been allowed to run off map which would have automatically broken line of sight and allowed for him to break the condition and re-enter the battle from another direction.