Wow, this is a tough one. There are a lot of people on my dad's side of the family who have depression, but none of us ever talk about it to each other, like it's a big secret or something. My best advice would be to talk honestly about your condition to your brother and let him know you want to give him whatever support you can, but don't put your own treatment on hold. Wrecking yourself isn't going to help anybody. Maybe talk to your therapist about how to set healthy boundaries when helping someone with depression?