postman, we had a similar, but not quite so difficult situation, when our daughter announced, at the age of 18, that she was gay. It wasn't a complete bolt from the blue to us, but nonetheless she had the courage to bring the subject out into the open.
To my knowledge, there are no homosexuals in either my family or in my wife's, for several generations, so our daughter was treading an unknown path in terms of how close family would react. I am pleased to say everyone has just accepted her and I think the younger generation of the family quietly admire her for her honesty. But it's less of a taboo subject for young people these days. And that's what I think (and hope) Daniel will find.
Best wishes to you and all the family, and especially to Daniel.