I'm thinking about how one of the twins fights for his brother's attention with his partner, because he wasn't used to having a "stranger" in their family.
This probably suits Bo better, but I can easily imagine Vincent in this situation too
Bo is very overt with his unhappiness. He's openly scoffing, saying mean things within earshot, making sure to exclude you whenever possible (makes just enough food for everyone but you, ect), maybe even bumping you out of the way. He was very much the "you can't come into our tree house club" type as a kid. Goes out of his way to get Vincent's attention- it's the nicest you'll ever see him towards his brother, while simultaneously guilt tripping him. Locks you out of the house all the time but pretends there's something wrong with the door. He's not good with having to share his brother- even if they weren't super affectionate before you came along.
Vincent is a lot more passive aggressive when he gets jealous. Makes sudden/loud noises to get Bo's attention back (slamming doors/things on the counter) Leaving notes for Bo in plane sight, signing to just him and suddenly stopping when you walk in the room. Makes a big deal about locking himself away for the day- signs things along the lines of <well, you clearly don't need me here....> Leaves for long periods of time, but frequently peaks in/makes trips thru the room while pretending to be busy but is really just doing it to interrupt you/spy. Makes sure you know that he can be anywhere at any time and you're never really alone with Bo
