NoDirection, I understand fully, as you know my W mothering skills are terrible, she has done a lot of damage to my kids, and short of a miracle will ever save their relationship.
If you feel that your W is doing that kind of damage to your son, then you are right, it is time to act, take full custody of your son, it sounds like she doesn't even want to be a mom, at this point, but if she ever comes around, don't deny her that privilege. I've told my kids, that if need be, I will fight for full custody of them, as well, but I would never deny my W her right to spend time with them, even though she has tried to do that to me. D sucks! but you have to do the right thing! Take care.