I'm generally quite a stoic person, I let go of what I can't control and choose to spend time with people I like.
Long story short, having a high-school reunion and a friend of a friend is attending. I used to get along with said friend of friend but this was about 8-9 years ago- I've grown up, things have changed.
It seems like I live rent-free in this guy's head and it's his life mission to put me down and get a reaction out of me (he doesn't do this to anyone else). We tried to have a call between our mutual friend a while back and somehow everything I think of him, he happens to think the same of me: emotionally immature, needs therapy, needs to grow up and stop being a child.
Whilst planning this reunion, here are some of the things he has said about me (in a big group chat with +50 people in): "can't wake a person who is pretending to be asleep", I need therapy, I should just grow tf up, to go back to my minimum wage job (I work in corporate finance).
Background on the type of person he was/is (he admits he hasn't changed at all since highschool). Once at a party, I said something he didn't like and instead of telling me that, he poured a shot of vodka directly into my eyes and refused to apologise or admit wrongdoing. Making jokes about your family, friends, hobbies, interests (jokes that only he finds funny and laughs at- everyone else is just silent).
I don't have any contact with this person but he will be at the reunion. When he does what he usually does (especially in front of old highschool classmates I'm trying to catch up with), any tips to go about it?
TLDR: unable to avoid childish, petty, low-eq person at highschool reunion. Any tips of composing myself or handling people like that?