Helping a drug addicted ex

I apologize if this isn’t the best group for this topic- I really dont know where to put it and I really wanted advise from people who don’t know me personally. I also apologize for the long post.

I dated a guy (let’s call him B) for 4 years. We were young (early 20s) but so intensely in love. We broke up almost exactly 3 years ago due to his drug problem (mostly). He developed a cocaine habit that turned into more of an addiction towards the end of our relationship. I couldn’t handle it and he wasn’t willing to get the help I thought he needed. Fast forward to now- we’ve both moved on, he has a 1 year old with another girl, I’m happily in a relationship with someone i really love. B and I very rarely speak or hear from each other aside from maybe once a year if that to catch up with each other. I always hoped that he cleaned himself up since we never chatted about that once we broke up for good. I recently came across a post he made on a website specifically for drug info/use/recovery that i knew he used since we were together. Its similar to glow in that it has threats and posts from people all over the world. I occasionally would look at his profile to see what he’s been up to drug-wise. A couple weeks ago he made a post talking about how his addiction has escalated quite a bit and although he’s a functioning addict with everything going for him on the outside, he still can’t get ahold of his addiction and is hiding it from literally everyone in his life. He mentioned that he hides his bags in the pocket of his jeans but is afraid it’ll fall out and someone in his house will find it. That concerned me because he has a 1 year old little boy!

He clearly needs help as he has tried and failed to quit on his own/with a cousellor in the past. Although I’m not a part of his life anymore I do care about him, his family and his kid tremendously. He was such an incredible person and it scares me knowing what he’s doing to himself. It’s out of the question contacting him to try and help because I know hedbe nothing but embarassed and would never follow through with help from me specifically. I’ve also considered contacting his on again-off again baby mama and explaining what’s going on but i know she’s not my biggest fan and she would only think Im trying to get involved in her business/back in Bs life. I also have no idea how much she’s aware of and what she knows. My only other option would be to try and contact his mother who i had a really good relationship with but idk how she would take the info. if i did say something to her I would ask that she doesn’t tell him how she found out this info because i do not want to get involved with his life or in the middle of his relationship. I’m just genuinely concerned. Or should i just stay out of it and keep my mouth shut? I would hate to see him spiral into a full on addiction and tear apart his family but idk if it’s really my place to say anything.