Idk how to address this

So my boyfriend has two siblings and his little brother that he’s closest to either really don’t like me or use me as a loophole to make him do something this morning I wake up check my phone as usual an me an my boyfriend both have each others Instagram an our account is added onto one another’s so I wake up check my notifications an his brother texted him “why you actin like that” “ you only care about your damn girlfriend” an this isn’t the first time where I had a strong feeling he just doesn’t like me an that his brother might think that just because he doesn’t do one thing or act a certain way its because of me but the girlfriend who’s like yea just go have fun text me when u get there text me when u otw how type I would truly hate to get in the way of there relationship with ours we are long distance so it’s not like he’s seeing me every night and day