It sounds like the husband wants to just continue biting his tongue to maintain access to the children, but LW is uncomfortable not standing up for her son and what she believes is right.

Huh. I had the opposite impression. LW wants to invite her daughter and son-in-law to the celebration weekend to maintain family peace, whereas her husband is ready to cut them from the invite list because of their treatment of LGBT people generally and LW's son specifically. It seems to me like the husband is advocating for the more confrontational route.

Boozy weekend of which I am mildly jealous aside, I sympathize with LW and her husband. They want to do right by their son and by their grandkids. They're in a tough spot.