He needs to read "Not Just Friends".
problem is, most the time he is unwilling to admit he still has a "problem".
Thing about this is, if he sees nothing wrong with himself, why should he change? His changes have to be from the inside of himself,
or the change is not real. Kwim? The saying "You can lead a horse to water but you cant make him drink" is very true in this case. Not saying that to scare you. But to prepare you. Until HE decides he has a problem, until HE makes the changes, it would be in your best interest to keep your shields up and your guard sky high.
Introducing him to SI could be helpful. Have a game plan and boundaries for one another. Will he know your username? Will you know his? Will you stay off one another's threads? That kind of thing.