u/Full_Economics_9539

So my 3 month old Siamese we had gotten first and he's was the only cat not pet(9 year old Chihuahua) and we were given a 5 day old (at the time) kitten for me to care for since I had done this before (bottle feeding) and now that she's old enough to start moving around some outside her crate (large popup crate in our bedroom) he will go after her or anyone holding her even though we've let them get used to each other slowly and he will sit outside her crate smacking or body slamming it even climbing it. If my husband holds the kitten he won't attack he will lick her but if me or my mother in law holds her he trys to bite her or smack her. What can I do