Hi Red, interesting question. Of my older children ( who can remember me being a drunken nightmare) my eldest son does drink a lot, none of the others do and none do drugs either, but when I was a wreck, in and out of prison of course it affected them negatively. I was very lucky to find a very good woman who levelled me out and welcomed my children as her own, without whom we might have all ended up very differently. Now I think their experience of me drinking etc has actually made them aware of all sorts of situations and things they would otherwise be ignorant of and I think they are fairly tolerant for it, albeit I wish I had never been such a poor role model in the first place. Of my younger children, only my eldest daughter is really old enough (13) to comprehand what I used to be like, and she never witnessed that first hand, but like her older brothers is a very level tolerant person regarding people with addictions, the littler ones clearly haven't really got to the point where they think about it really I don't think.
My own father was a drunk but was also violent towards his family ( I was never that) and with hindsight I can forgive the drinking but not the violence ( which came whether he was drunk or not), but I can see both his drinking and his anger were symptoms of feeling very very badly about his life, the reasons for which though still escape me.