What to do about my dad? Warning long drama filled post

So my dad has a problem with my aunt. And we got in an argument about it and i want to know what I should do.

My dad says my aunt belittles him and has lied to him and my mom several times.So now whenever any family event where my aunt is around he constantly says snide remarks because of his anger toward her and has now decided to cut them out of any family events.

I know my dad sometimes gets offended by things that were not meant to be offensive so when he says she has lied to him i doubt it because all I have seen is my dad belittling my aunt and have not seen my aunt to anything wrong. And it bothers me how he treats my aunt and how he talks bad about her all of the time and honestly am tired of hearing it and think hes acting like a child being that he has to cause a big scene at family events over small things and even at my wedding. And now we cant have family events with my family and my aunt anymore because of my dad which sucks because i enjoyed them.

So today he was complaining about her and i told him that i thought that he was the one starting the drama all of the time. He got really pissed and said that he would stick up for me but it hurts his feelings that i wont stick up for him. And now its super awkward between us because he resents me for basically siding with my aunt.

What should i do?I want to move on from this. Ignore it?Talk it out? I still want to see my family...

Sorry for the super long post guys