It may seem hard now just finding out what you're brother has been through, and i'm sorry to hear that you are feeling down because of it, but think of how hard that must have been for him to open up to you. Just the act of him doing that himself shows you how much he trusts you and values your opinion and support. Try not and get down on yourself for not being there for him as much as you would have liked, in your defence you didn't know. And now that you do know, you can be there for him to lean on you a little, just as he as done for you. Don't beat yourself up for it, think of it as a good thing that he felt he could be honest with you Hang in there.