Art - I don't know which would be more useful to you right now - "There there I am sorry it is so rough" OR
"Stop, breathe and remember you have not been a bad mother. Throwing yourself on some self-sacrificial pyre for imagined and/or exaggerated wrongs is possibly a tad over the top. Taking care of yourself is not selfish. You being miserable and overly self sacrificing will not help your son or yourself"

Seriously - no parent is perfect, offspring do have troubles no matter what the parent does (and it is not - seriously not- good to protect them from all bad feelings). You all have a plan for getting him some counseling and he lives at home and you all are helping him with his car, etc. He does not have a bad situation - even if he needs some therapy to help him deal with his feelings.