He needs your support more than ever now. Suicide attempts are hurting oneself reather than others, he could probably use some professional counseling. You cannot change him, keeping good thoughts of your friendship will help support him through this very choatic time.
He is still your firnd the one you knew, he is just needing some extra help with whatever has been eating away at him (for years probably) These kinda of behaviors don't ususally manifest tin a couple weekd or months. He is in pain. You do not need to change him for the better nor lecture him on his abusive behaviors.
He is the only one that can eefect change, but he can use a good friend now. One that can't see him as anything other than his friend. He knows the behavior is inappropriate, you don't have to remind him