Brother and sister in law trouble

Future sister in law. They get engaged in June.

Never been oober close with my brother. Hes very surface level with me and my parents. Loves his friends/ friends family. Not sure what we did wrong truthfully.

He knows i feel this way and he just says hes not aware of it and he doesnt try to act different with anyone. Which sounds like he is simply uncomfortable with us. Hes a closed book other than that.

His gf is 22. Im 24. My bf is 25 . He is 27.. My bf describes his interactions the same.

We all had a big fight when they abruptly moved out of our place. If you want the details let me know but to keep this shorter, we didnt do anything wrong (literally ive analyzed this from all angles for 2 months) - my brother apologized in the end saying they were in the wrong. Never heard a sorry from his gf (she lets ppl clean up her messes). Just that shes worried we wont get past it and itll always be awkward.

He is mean to my mom a lot. Hes a hot head, his gf is a bratty princess. My bf and i hold our tongue a lot, we dont say anything mean or retaliate. We take it. Theyd lose their shit if we acted how they treat us. Not sure if i should talk to my brother or accept this is my family and to keep them at an arms distance. I feel a ticking clock with the engagement planned. I dont care if he calls it off or marries her. His life. As long as he is happy, i just can see theyre a firey match and they both need someone calmer. Hell maybe its a match made in heaven , who am i to say.

Maybe they need to grow up. Idk and all i wish is we could all get along and be mature and not feel the distrust they caused and the uneasiness. Its festering which is on my bf and i to make the effort to fix it. They just keep knocking me down but i think progress has been made.

I feek bad for my parents mostly. My bf is sad cuz likely this could be his future family- his family are basically saints who dont know the word drama- im lucky to have them. And he is lucky too.

Sorry for the lengthy post- im truly a yapper. And unfortunately i feel i answered my own question but want everyones thoughts and ideas, maybe similar experiences