Mordekai will stand and once again cast Eldritch Blast at point blank range at the Mother (Meepo's advantage has now worn off, and rolling with disadvantage for a range spell at melee range!)

Attack: 13 Damage: 14 

No, mordekai still has the advantage until the end of Meepo's next turn, so till after Meepo gets his shot off.

(I think Meepo's 'next turn' has already happened by the time Mordekai is up, though? Meepo is before Mordekai in initiative, so by my reckoning last round you used the ability, then I missed with Eldritch Blast anyway, and this round you shot the crossbow, and my turn is after that.)

(OK... I was just going by the DM's note, mordekai's action, then the bad guys, then Meepo's action...)

(OOC: DragonDenn is correct, you still get advantage from his ability.  We're technically only in the 2nd round still until your action, and the 2nd round was when Meepo did his ability. Then we move into the 3rd round.  I think Meepo stuck a crossbow shot in there a bit early which is confusing you. That said, you rolled a 4, then an 11.  So, even if you had no disadvantage, your first roll was a 4 and a miss.  So, we'll just keep moving!) 

Mordekai's blast of energy zaps wide of the enemy who continue their relentless attack.  

(OOC: START OF 3rd ROUND)

The father angrily lunges at Olin, attempting to bite into his shoulder with her pointed teeth that fill her grisly mouth: 8 Damage: 12

The mother meanwhile continues the disadvantages Mordekai battling her as she swipes again and again. Attack: 16 Damage: 14

 Meepo fires a crossbow bolt into the mother who is most injured.  It slams into her side, spraying black blood across Mordekai and the wall.  

Kane also tries to shoot the father, who is battling Olin in front of him, the torch dropped to the ground and spluttering so he can reload and fire from his sitting position against the wall.  Attack: 17 Damage: 9. (I didn't give him advantage last round, so i'll do it this round). 

Mordekai slumps backwards as the Mother claws him across his chest, his eyes fluttering into the back of his head.  She spins, crouching and feral, eyes on her next target, Aga. (Mordekai, in case you quickly become conscious, also roll a CON Save DC 10, as you also may be paralyzed)

Olin, no Con save required for the bite. 

Kane's arrow slams into the father who screeches in anger, black blood spraying across the room.

AGA, take your action, no advantages or disadvantages that I'm aware of.

OLIN, take your action, same. 

Meepo and Kane have taken their 3rd round actions already.  Mordekai is unconscious. 

CON save: 16 

Olin, badly wounded yells, "Get back up, Mordekai, we need you here!" and casts healing word on him for 6 healing.

Olin swings once again at the Father, trying to bring him down: Attack: 6 Damage: 8

(Does this mean when Mordekai gets up he won't be in melee with the Mother? 

Mordekai opens his eyes as a flood of magical energy heals his wounds.  The body, still fighting the paralysis from the strike shrugs it off and his limbs respond.  You are prone.  You are still technically in melee since she's an enemy combatant standing next to you, she hasn't had a chance to move and attack anyone else.  But on the plus side, you can act this round!

Aga will strike at the Father with her lance.

Attack: 10 Damage: [roll](if([roll:-1:critical], =0, 1d12+6, 2{1d12+6}.expand()))

Then will take a bonus action to bite: Attack: 12 Damage: 9

Meepo will send Rat in to give the help action to Mordekai.  (Gives advantage on attacks against the mother...)  Rat has his own initiative, so can move at any point the DM thinks it is allowable.

When it is back to his turn again Meepo will again send another crossbow bolt at the mother...

Attack: 24 Damage: 6

Ok, then if the DM approves of the advantage given by Rat, Mordekai will stand up, and once again cast Eldritch Blast at point blank range. 

"STOP MOVING!"

Attack: 17 Damage: 8

(If Rat isn't able to help, Mordekai will use action and bonus action to attack with daggers instead. Let me know if you want me to roll and use this instead.)

Aga's long lance swings around in the tight quarters, missing the Father, as she also lunges in, trying to bite the putrid undead creature, but it's slams it's shoulder back, her teeth raking off of its tough flesh.  Rat runs across the room in a wobbly run, leaping to the bed, then leaping into the air flapping near the mother who distractedly swipes at it.  It distracts her enough that Mordekai, pushing himself up off the ground can unleash his blast which slams into her.  She stumbles backwards against the wall, her dark eyes wishing evil upon the room, but is still standing.

Olin sweeps his staff past the father missing in the chaos of the melee after healing Mordekai. 

(OOC: Start of 4th round) 

The mother shrieks angrily and attacks the flying cat that's distracting her.  Attack: 22 Damage: 12. 

The father continues to take swipes at Olin, hating the priestly power emanating from him.   Attack: 6 Damage: 12. 

Then Kane fires another crossbow bolt, while blood leaks from him onto the floor, shooting at the father. Attack: 12 Damage: 7. 

Meepo shoots the Mother, the bolt stabbing into her throat.  With a gurgle she hits the wall, clutching at the bolt as she sinks into oblivion, her body dropping.

Olin, Mordekai, and Aga, take your next actions.  Only the Father remains active (aside from the undead that ran off).  Meepo, how many HP's does Rat have?  I assume Rat is slammed out of the air, hits the ground and slowly dissolves out of reality. 

Yep, Rat is taken out with that blow.

Aga will go for a kick at the father, then another bite as a bonus action.

Attack: 23 for 5 damage

Attack: 16 Damage: 9

Mordekai looks across at Meepo and nods. "Thank you, friend." Then free to move, he'll back right into the far corner of the room and his eyes narrow as he casts Eldritch Blast once again, this time aiming between his allies straight at the Father's head.

Attack: 11 Damage: 12 

Meepo, a bit regretful of losing his familiar, even though he knows he can re-summon him, lifts his crossbow and takes aim at the father now.

Attack: 15 Damage: 5

Olin swings at the father again, Attack: 18 Damage: 5