What is the most christian thing to do?

Tell him how much you care about him and all the good things going on in life. Tell him all the trauma it would cause to you and others who care about him. Tell him that if he dies it will screw up your life and other people's lives. It's not for him to live its for you. Tell him that if he isn't going to live for himself tell him to do it for you at least. Tell him you need him in life and that you cant live without him. Tell him all the things he would miss out on life.