I think the most important point is that you should avoid showing any kind of anger or disrespect towards him, he might jump into bad assumptions especially with that girl besides him. maybe you should talk to your brother [in private, go for a walk or so] and tell him no matter is his decision about that girl it’s his call, and you and your mom won’t interfere, and would always care for him. but most of all, tell him that family is something rare he wouldn’t find another family but he could find another gf, he can start a new life but that doesn’t mean he should break up with his family or be rough ..you know sort of that [note; don’t lecture him, just tell him kindly and he’ll get it... been in the same situation]I cried last night for and hour and a half and again this morning for another half an hour. (*Im not one to normally cry either*) My brother has a new girlfriend, don't get me wrong, I like her, but there is something that is not right about the situation. I had a nice long talk with my brother about it, I think I will have a 'lil chat with her and find out what it is. My brother is acting differently, but I don't think it's in a good way. I know she is not here to take my spot, but there is something that's making my brother kinda mean and sneaky. I love him to no end, and I don't want to see him get hurt. I care too much for him. I could go on for hours here, but I just don't know what to do or say at this moment. I told mom and she is going to have a talk with him today. She is slightly worried about him too. We know he is a big boy, but we are still family and that will never change.