I have recently found this http://locate-lawyer.info/ you tell them what the prob is, they'll send it off to their lawyers who might or might not get back to you with a quote.
You then decide who to go with.
It's free till you choose someone, then obviously you pay the lawyer. You don't have to follow through with anything so you might as well try it
I am not an attorney but familiar with similar cases.
Generally if he is unable to care for himself he cannot care for someone else.
If he is under the influence frequently, he cannot care for children, cannot drive them anywhere under every state law (DUI), and places them in harms way.
Is he or does he have a tendency toward violence, anger or hostility or does he just have an alcohol problem?
In case no follow up - he needs to get help. The court can order him to a treatment which he will eventually appreciate if he really cares about his kids.
Any time he is not in sound mind (intoxicated) you should make sure you take the kids. You should explain that dad has some issues that he needs help with, and that you hope that the right doctor can help him soon.
Try to make the transition as pleasant as possible. Try to avoid arguments of any kid when around the kids and him. If he becomes difficult when drinking and resistant, the police or child services can intervene if necessary.