As long as you expect chaos, go for it.
A lot of children grow up without fathers and don't turn out wrong. I don't know how old this daughter is, but she is obviously eighteen or older. If you feel you can keep your marriage intact while going through another difficult child with issues, let him give it a whirl. I'm not psychic, but my guess is it will not go well. And I don't know how he'll feel about throwing HIS daughter out of the house. Your son was YOUR son. This is HIS daughter. It does make a difference, since neither of you raised one another's childrens. Thus a strong attachment from either of you is not there for the other person's child.
Crossing fingers, eyes and toes!!! Good luck!
