Worried about SIL and 17mo nephew (long)

I want to start by saying that I am not the only one who is concerned about this, but that nobody has said anything about it. ---- My sister-in-law ("Lauren") is wonderful in so many ways. She makes my brother very happy. She has some pretty serious issues, though. Lauren was overweight in middle school and began doing drugs in order to lose weight. She dropped roughly 100lbs in a very short time using pills such as Percocet and prescription diet pills. She most definitely abused them. Her mom also has a serious drug problem, as well as other members of her family. Lauren is also depressed. She posts regularly on Facebook about suicide, depression, and anxiety. She refuses to seek help. Lauren now says that she is not on drugs, and hasn't been since high school. She takes an antipsychotic medication that was prescribed by a doctor, and that's it. Anyway, Lauren pops pills like tic tacs. She'll come over and in the course of two hours, take 20+ pills. I don't know what she is taking, but it's excessive. It's also worth noting that Lauren has more than doubled her weight in the last 4 years, which I only mention because that's what led her to start abusing drugs in the first place. ----- Lauren and my brother have a 17 month old little boy, who is the light of my life. The issue here is that, if my nephew so mush as sniffles, Lauren whips out medication. I'm worried. I'm worried about Lauren, that she might (or already did) relapse, that she is struggling with her mental health, and that she is putting herself at risk for liver/kidney issues with all the pills. I'm also worried that she is overmedicating my nephew. My brother doesn't even seem to notice. And I recognize that it really is none of my business, especially because I don't have any children, but I can't help but worry. My mom is worried too. A lot of people have noticed. Is there anything I can do? Are there things I should watch for? I love Lauren and she really is such a great mom and a great wife. I would really appreciate some input.