Re: Lesbian/Gay
In response to the OP, I would just tell them that I'm not their type, but not severe all ties from them or anything. They were a friend and will always be, changing their lifestyle or disclosing something about it would show that they trust me, and I would never want to betray that.
However, my response might be different depending on whether the person is Muslim or not. If Muslim, I would try to show him/her after a few days how islamically his/her choice is wrong, but would give them a few days to recover. If not Muslim, then they have their own belief and I won't interfere, just keep supporting them like I did before.