I have 2 thoughts here,
1. IMO it is never okay to leave a child alone with an active alcoholic. My AH only has supervised visits with the kids. I cannot trust that he will be sober. He could be sober when I drop them off and then drink while they are in his care. Then the breathalizer is useless.
*backstory* My AH ONLY drank at night, so at one time I thought it was okay to leave him alone with the kids in the morning so I could run errands. It worked for a while until I arrived home at 11am after being gone 1 hour and he was passed out drunk on the couch. The little ones were upstairs with older dd (thankfully). After that....never again.
My second thought,
If the child has a sober person their to care for them while the A is around, I think that is ok. I mean I lived with my AH and our kids for many years before I left.
I try to remind myself that.... I will never know enough about another persons situation to know what is right for them.