If Bobby Christina is 18 and is not under anyone's legal supervision, whether she sees her father or not ought to be totally up to her, period. I have no idea if it would be a good idea or not, but it's her decision to make, as she's a legal adult.
I don't care one way or another about Whitney's sexuality, but it's an unfortunate time for rumors about her being a closeted lesbian to be resurfacing, simply because it may lead to idiotic protesting of her funeral. That sort of thing just infuriates me, because funerals are for the mourners more than the deceased, who's obviously past caring about the actual funeral and past the possibility of being hurt by protestors saying nasty things about them. So, really, what's the point? Okay, I know what the point is--to get their nasty signs on the news. But beyond that, what's the point? Making people who are already feeling terrible feel worse just is needlessly cruel and, IMO, not at all a Christian thing to do.