Dad/Mom is a thing, though Dad is persuaded none of the kids have figured it out. (ha. ha. ha.) Bro=>Dad is also a thing but Bro has Major Issues about sex and love (namely he finds them utterly incompatible, seeing as he associates sex with baser needs at best and violence, contempt and degradation at worst) so even though Mom wouldn't mind sharing Bro so far has refused to entertain the idea.

John might be one of the scariest, though! he just doesn't THINK he is. XD