I really don't want to feed into the paranoia theme, but if your AH is paranoid/mentally ill (I don't know if he is, but he could be + drinking + on Paxil + watching his life fall apart, he is very dangerous to you and your DS. He is unstable, unpredictable, and a threat.
I can't put my finger on it, but that letter bothered me. Less if the usual "woe is me" manipulative A behavior, more detached. Just my personal thoughts.