It seems like you liked his attention, perhaps because of your own need for it. It could be any other guy.

Also, you have that feeling of “hmmm but he might get better, improve himself”… he might, its good you have faith in humanity. But, sometimes that just leads us astray. How are you gonna do that? If he wants to improve, he has to confront his issues! Are you gonna help with that, or even confront them by telling him? If the answer is no, then just leave him. You know he~’ll probably like giving girls attention (thousands of female facebook friends), so he’ll come back, you’ll enjoy this feeling, and tell yourself you’re helping him… but really you’re helping yourself, for a bad reason, thats why you feel uneasy.

If you want to help him sincerely, challenge. No change happens in a state of equilibrium. He clearly has issues he cant deal with, so address them if you want to. Otherwise, leave it.