Is 3 1/2 hours too far away to come home for the weekend?

Yes, I’d be concerned that even coming home once a month or so (and having to travel 3+ hours to get there) could interfere with your studies and your life at school. And agree that finding some local resources to help out your brother sounds like a good idea. I assume your brother is still a young guy and that is a lot for a young person to be dealing with. I didn’t really have to deal with caretaking issues regarding my parents until my 50’s and that was tough enough. I can’t imagine having to deal with all of the stress and complexities of that as a young person. Good luck to you and take care of yourself too.