To answer the original question about your grandparents.....I would say that they have not changed their opinions about gays and we don't know what they say and think in private. Most people, around family, wouldn't act like they didn't want to be around a gay person but we don't know what they really think. I mean........ it's your uncles life and he should live it the way he want's........It's your grandparents life and they should be able to act decent around family even it they don't agree with the life style.......you have your life and you should live it as you see fit. Also your grandparents may have taken the stand that they don't want to Judge or distance their son.
Peace to all