what to do about a family member?

My brother has been having mental health problems for months. He used to be close friends with a guy that I thought was cruel, but from what I have heard from my brother, he may very well be a psychopath. They've been friend since highschool, for about two decades. My brother is going through a lot recently, it's obvious his thoughts are dwelling on unwholesome, violent themes, just from talking to him. I had to point this out last time I saw him. He is baptized and confirmed a Methodist, but not a churchgoer for decades. I've encouraged him to seek out therapy. But my guess is he doesn't realize what's problematic about his behavior, or how ultimately self-defeating it is.

I'm not all that close to my family. Since my decision to return to being a regular churchgoer about a decade ago, it has been a source of difference. The rest of my family doesn't think God is all that important, and they have a cynical attitude towards any kind of personal faith. I think esp. the gay issue has hurt them, because my mom and my dad have had close gay friends.

Honestly I think it would take a miracle for my brother to change anything in his life. He is so stuck in his ways, reacting to circumstances. His life is centered on fear and insecurity.

The past month I've been "haunted" by the fifth commandment, and how I don't really take it all that seriously the fifth commandment was for "other people". Then I gradually became aware of my family situation and why I don't take it all that seriously. Because my family is a mess and I feel I'm powerless to do anything about it, it's easier not to care. I'm really at a loss what to do. My heart tells me this is what life is like when you don't have faith in God, a demonic focus on self-protection and security creeps in and takes over your life (I've been there and felt that, I live in a rough neighborhood and for a while I was seriously obsessed with crime to the point I was starting to lose my integrity), but, I'm at a loss how to "share my faith", since my faith is so weak and I am wary about 4-spiritual laws style evangelism.

Maybe I've already taken the first step by pointing out how what he's feeling is something he needs to work on.