SS, I hear you saying it depends on the role of a person. I disagree. Tough love is tough love. Maybe your son is manipulating because he knows you won't let him fall? A son's familial ties are not stronger than a husband/wife. In my opinion.
With all of my challenges with AH, I have not mentioned my son who seems to be taking the same path. I let go of son when he made his bad decisions, I don't feel it is different than with his dad. Son knows he can't manipulate me, so he has been working on a brother. I am helping the brother stay strong by teaching him what I am learning. The A's manipulate. They certainly don't feel the loyalty you are clinging to. You can let go if you want to. Maybe you don't want to? that is what I am hearing.