It's a difficult situation and your husband needs to put his foot down. I'm lucky that most of my family absolutely adore Marvie, however the only person I had trouble with was my Dad, who had his concerns.
He made a few comments that probably stem from the 'Daily Mail' / White Man-Thai Bride Stereotype, before he event met Marvie and didnt really make much of an effort with her the first time they met. We cut off contact for about 3 weeks, and the rest of my family gave him a lot of stick and since then he's taken the time to actually respect her as an individual. It wasn't easy for me to do that to my Dad, and it won't be easy for your husband to do that to his brother, but he has to make his views clear. If you are the one arguing etc with his brothers, they'll just use that as more ammo against you.
