Welcome to YT. My only advise is to have patience and give your furbaby (what is his name?) time to learn to trust and bond with everybody.
Positive reinforcement, slow actions and involvement with all family members is probably the key.
Your brother can help out in so many ways to help bonding, maybe a little each day.
Your Yorkie probably has never known how it feels to be safe, secure and loved unconditionally so he is overwhelmed. I bet in time he will come around and be the happiest, kindness Yorkie ever. He just needs extra hugs and kisses.
Keep us informed on his progress, thanks.
