i wouldn't second guess what the courts MIGHT determine - i'd ask for everything - sole custody, LIMITED supervised visitation, NO overnights, possibly breathalyzer prior to visitation. if your attorney won't back you up 100% on this, you got the wrong attorney. the children "should" have a guardian ad litem.......whose sole focus is what is in the best interests of the children.
they are 5 and 2. its ok if they mention "missing" dad after a couple days - that doesn't mean they know what is best for them. they probably also would like ice cream for breakfast, doesn't mean they get it.
please don't get hung up on this "need a father" bit - he has demonstrated he is incapable of being a responsible adult and has in fact been a DANGER to the children's well being.