BF’s Brother Doesnt Like Me

Just for a little back story me and my boyfriend met in college and have been together for almost 4 years. Around that time his older brother lived out of state so we hadnt really formed a relationship.

He just moved back because of the pandemic and of course we all chill and hang out together sometimes. At the beginning it was so weird having him around so much so fast (like we went from a duo to a trio). We even went to lunch to get to know each other better and he admitted he misjudged me (I didn’t ask what his opinion was) but after we were cool, laughing and joking with each other.

Almost a year later, I’m starting to sense the same kind of tension from the beginning when he first moved. He always makes weird comments (about my looks, whether I cheat or not, if I’m “using” my bf) and just overall little subliminal messages. To the point my boyfriend has questioned me here and there. And it’s REALLY starting to get to me hearing little comments here and there.

When I first noticed I told my bf and he just laughed it off but now he’s see’s it too but tells ME that his brother is “just joking” and it’s not that big of a deal. I would never try to make my bf choose between me and family that’s just awkward but I feel like his brother doesn’t like me. And overall idk what he says behind my back especially if my bf is going to randomly question me. What can I do in this situation? I feel like there’s nothing I can do/say to resolve this cause he obviously formed his own negative opinion about me.