They've said multiple things, multiple times about it, they have said to use the they/them pronouns, and a lot of people have, but a lot of others haven't and keep calling them a girl
I sounds evil but meh my sibling used to be very mean and annoying ya know what I did? I got dirt on them told them if they didn't improve or be nicer I would snitch, so basically I black mailed them their better now and it never had to resert to snitching