If he is dangerous, then I would do the full custody.
Drinking and driving was not an issue for us, because my A would not drive when he was a drinker.
The emotional ramifications are exhausting, even if you do not choose to maintain full custody. I have maintained primary custody, and my RASTBex has visits. He is sober.
When he was drinking, he had visits, but I had to be very vigilant, had to make constant boundaries, and not doubt myself. I had to make a lot of judgement calls.
Luckily, when my A was drinking, he was extremely over protective and vigilant himself, but, even that could sometimes cause our son some anxiety. I think that being around an alcoholic parent all the time is very damaging to kids, in ways that are not upfront obvious in the moment.
When our A lived with us while drinking, which he did, off and on, I had very clear rules. If he did not abide by the rules, he was ejected from the home. Then, I finally wised up, and he was not allowed to come home until sober, as in, in recovery.
he did go to rehab, but is now unstable in other ways, and still only does visitation. He has lived with us since rehab, but, I still had to put him out, due to poor judgement on his part, emotionally.
I think it is wise to recognize that you probably have the better judgement of the two parents.
Full custody does not prohibit visitation, correct?
He would have to prove he was sober in order to drive them anywhere.
Just FYI, when I restricted his access to his son, and put him into child support, those were some of the things that lead him to his bottom. And he sought help.
Not that its been a joyride since, but, at least he is not lousy drunk.