Husband lashed out on me

My brother has been struggling with addiction for a few years now. It's gotten very bad lately and it's been wearing on the whole family, which I'm sure has not made me very easy to live with. The other day I confided in my husband that I always blamed myself for my brother's drug use (because I'm the older sister, and I'm supposed to protect him. And because he started experimenting when I went away to college).

Anyways, some background- my husband used cocaine before we started dating. I told him back then that I didn't want a relationship with someone who was using drugs. Lately, I've been wondering if he's using it again. I could be paranoid because of my brother's problem, but he's been sketchy with his phone and staying out with friends late (and no, I don't think he is cheating). A couple days ago 80$ went missing from my wallet. I was already stressed and started asking him if he took the money, because there was really no one else who would have. He denied it and got very defensive when I asked if he was doing coke again. He yelled at me for not trusting him. What hurt the most, was that he said I am going to drive him to do drugs. I just can't take it anymore... This isn't the first time money had gone missing. It could have been my brother before, but he wasn't around this past time. I'm already losing my mind over trying to save my brother, I don't think I can deal with any more drugs...