This is for the people who reach the end of Tavern Talk, and spoiler of the ending.

Once you learn that your old friend is response of every quest you put and plan to ending the world, your friends and your drink going to stop your old friend from causing the world end.

Even they succeed, I don't think Innkeeper make a huge impact after picking the right drink for final quest. So maybe it one game suggestion, so here I got and again it spolier for the final part of Tavern Talk:

What if after their friends going to stop the undead and teleport to face Innkeeper's friend now BBEG who Innkeeper ran away after the friends TPK, facing their fear just to talk with their friend one last time before having a one on one battle. Imagine what Innkeeper been after 35 years of failure and regrets by leaving their friend behind by overcome their past with new friends, quest, skills and their reason to open a Tavern. Plus Innkeeper fighting BBEG just to aid their firends might turn 180. Innkeeper pulling every magic from forgotten past, full on fist just to punch BBEG hard, or go tactical wizard with every magic gun in John Wick.

Hoping this effect the ending of the game, but hope this suggestion might help Innkeeper fear.