While I appreciate that your mother has a medical background, if your brother is regularly putting himself in life-and-death situations, then professionals should be dealing with it. If you know where he is and he asks for help, call him an ambulance. If he is in serious trouble, he will get precisely the help he needs without emotions clouding anyone's decisions. If he isn't in serious trouble, and his cries are more of a plea for attention from you, then he will soon learn the consequences of crying wolf.