It really doesn't matter if your boyfriend is drinking alcohol, uber religious or likes sky diving ... If you do not approve, then you do not approve.
My wife and I have been married for 30+ years, we are blissfully happy and always have been. This is because we match at all levels: Similar origins, socio economic backgrounds, similar IQ and education levels. We have the same politics, same beliefs in society, same likes and dislikes. The same views on people, family and friends. What that all means is wholly unimportant, what matters is we match
My advice to anyone is 'Never compromise, only ever accept' .... Right now I would suggest you are compromising with your boyfriend's alcohol consumption ... My advice is do not. You have to either accept that he drinks, will drink and will always drink or get away. Realise that it is quite likely if pressures build such as having children, he will drink more and more. Drinking is a social crutch for most people. His need for 'family approval' is also concerning.
It is a reality of life that we cannot change people ... Plus if you look at his father you will most likely see his son in the years to come. We are all a product of our childhood and our surroundings as a child .... I do not think that you match and that you need to change your life; get away from this young man.
Fortune only ever favours the brave. The hard choice is invariably the right choice.