Martyr or Angel?

I recently learned that one of my good friends is not only a compulsive liar, but also has had suicidal and self-defeating thoughts about life. All I feel is empathy because I know what it's like to compulsively lie, and I also know what it's like to feel like there's nothing good in the world. On top of all this, my friend feels like they are a loser - and I also know how that feels, having been unemployed for months and laid up in bed with a broken foot.

When I've been down on my luck, I've always had a support system to rely on - whether it was my best friend who I could tell anything to and who taught me that you don't have to lie in order for someone to like and appreciate you, to those who believed in the light at the end of the tunnel. But my friend doesn't have the support system that I do, and so I feel that it is my moral and karmic duty to be that for him.

But part of me tells me that I'm just getting myself into trouble and it's not my job to fix people who are broken (per my track record of taking in strays) but another part of me is reminded of my duty as a compassionate human being to make the world a better place, one person at a time. It's amazing to me that even I, as heartless as I can pretend I am sometimes, know when to cast away my own petty needs so that more important needs can take its place. Maybe I am a martyr, for a martyr will suffer for what they believe in. But I'm also an angel, because they see no other choice than to invest in their faith.