>>5792He/him/Xhe/xer/it/that whatever, family is still family even if they troon out. That said I hope they didn't troon out but given OP describes them as living le van life I don't think they've gone down that rabbit hole since being a van nomad tends to be more of a masculine thing.
And if anything OP's cousin would probably earn a big raise if they stayed while taking the 'pink pill', we're talking about IBM after all and American big tech has that reputation for a reason.