Dear Nessie
I think the two posters gave you two different good options depending on which way you want to go. As I see it, both are valid.
Ksm kind of took the harm reduction approach. That is, not withdrawing support. The logic here is that it doesn't back your daughter into a corner-- and running to him, all her eggs in one basket.
And there is the 12 step approach of total abstinence in the second post. Withdrawing focus from your daughter into yourself and other family.
I think you can do a little of both. Stay supportive and connected to your daughter while you don't like her choices. If he's a drug dealer I think he sounds dangerous. I can see why you don't want him near the house.
My own mother married somebody kind of no good. My grandparents stayed in the picture helping raise us. They saved my life. I agree. You can't stop somebody from living as they choose. But relationships in some form can be maintained, if you choose
I am sorry you're going through this again.