Removing a gm on short notice?

My FH was in a bind a while back and asked someone to be his groomsman. He also asked his closer friend to be one (gm#2). GM 1&2 we’re together at the time of asking and two weeks until our wedding Gm 1 cheated on gm 2 and obviously there’s some tension.


That being said gm 2 is willing to still have gm 1 participate and has been very open with us and maintained communication throughout a crazy side gig season and while maintaining 4 jobs. Actively communicating and attending events (tastings etc when able to get them off work) offering insight support etc
GM1 has been refusing to communicate or make contact the entire time he’s been in the party, told me in front of my FH our BMs and store staff my opinion didn’t matter on anything when my FH asked me thoughts on colors for his vest and our party, has stated he’s refusing to speak, has been giving my FH massive anxiety over what he’s showing up in among other things and his main interest has been if we have an open bar (we originally did but thanks to financial strain due to unforeseen circumstances we’ve been forced to cut this recently in our final quotes and we can only imagine what his reactions going to be when he finds this out). He’s come up with the biggest BS reasons to not show at gatherings or events and always says he will then day of or the night before after dozens of attempts to contact and confirm in weeks leading up to said event he’ll cancel.
He’s more recently met someone he trusts and confides in way better than GM1 he’s like in the party who already said he’d accept with pleasure and support us both fully and speak at the reception etc.
How do we tell GM1 he’s no longer welcomed as a member of the party and quite frankly if he doesn’t want to come he can remove himself all together since he’s been acting like it’s this big inconvenience the entire time anyways?