NTA. I am coming from a place of personal experience. I grew up almost exactly like this. Both of my parents are alcoholics, and I had no idea how bad my childhood really was until my husband would point out things like that aren't normal. My dad's side of the family is also a long line of drinkers, and never discouraged any of how our lives were. It is such a weird feeling to have your perception of what's normal behavior in your family be challenged, and then to come to the realization that it's true. I've unfortunately made the mistake of allowing my kids to be with them overnight 1 time during a period of 'sobriety'. I won't share details here, but I can DM if you'd like to be able to share a perspective with your husband on how bad it COULD have been and why he SHOULD be going NC with his mom and anyone who supports her. Stick to your gut, she's already shown she hasn't changed. She will not ever change, and there's no need to expose your kids to what your husband had to suffer. He didn't have a choice as a kid, but he has one now.