Alcoholic MIL?

This is a really tough topic to discuss because I don’t want to feel like I’m trashing my MIL. She’s a functioning alcoholic (seems completely normal, goes to work, lives like a normal person) but has a drink in her hand the minute she gets home and is often pretty smashed before dinner time. I think she might also take prescription pills a bit more liberally than what she should.

My issue is, I don’t think she’d overstep any boundaries and get wasted while watching my baby, but what if? I really don’t want to start any problems with the family, as her choice to drink is none of my business, but I just want to know that she has enough sense to lay off when the baby is with her. Should I just keep my mouth shut and my eyes open? My FIL would probably be there most of the time anyway.