Both of my Grandfathers were. I can't recall my one Grandpa drinking - I think he may have stopped before I was born. He was diagnosed as bipolor shortly before he died though which helps to explain his behaviour.
My brother is an alcoholic. As well as one uncle and one cousin.
If there are more, I am unaware of it.
On my ah's side, I think there are quite a few. I don't know many of them and don't know them well but from of the stories I've heard as well as knowing that many of them still drink quite a bit, I think they drink too much even if they aren't alcoholics.
Yes, I do worry about my kids. I have talked to them and tried to educate them and warned them about the risks and how it's even higher for them. Having grown up with their father, they all are pretty anti-drinking. They are teenagers now so only the future will really tell. I just hope that they hold strong to the way they feel now as they can see how it's destroys people's lives.
On a sidenote to that, I worry also about their emotional wellbeing due to the fact that they didn't have a great role model for how relationships and love are supposed to be. I worry about them emulating what they saw growing up between ah and I. I've seen some of that codependancy in my oldest son. That worries me as well.