Also the impression I got is that at least these days, most foster systems do their best to make it possible for the kids to still have contact with parents, as long as it isn't judged dangerous to them! Which makes me think this guy didn't just make a decision to let her go into care, he actively cut off contact.

(Whereas from the way he tells it in the letter he doesn't seem to have ever made a single decision about her ever, things just 'happened' inevitably.)