I felt my boys were not wanted at my dads house so when I went I left them at home. My dad (who has always LOVED animals) just didnt seem to bond with them at all. I made my visits less often and shorter and unfortunately left my dogs at home. I don't think my dad cares either way with my boys, but his *beep* wife cares and makes a stink to him after Im gone. I despise her!
Anyways.... Id just leave your babies at home and visit for only 2 hours tops... you can see your neice still go through everything. Also, invite your brother to your house with your neice. Offer to cook dinner or something. That way he cant complain about your dogs in YOUR house.
Good Luck!