I think Brian failed because he hurt them both in the process of trying to help Justin. I said he didn't fail because he didn't want to help, because he didn't love him, or because he didn't try hard enough, but because he emotionally catabolized himself to do what he did, and then there was that terrible backlash.
I do believe it's a failure when you set out to help someone else and end up hurting yourself AND the other person. But it doesn't mean you didn't try or that you didn't care about them.