If you are serious about getting them help and they are unwilling to get help themselves, there may be a legal way to get him help. It is a last resort only... and it does not force him to go to treatment, but it court orders him and he may stay a few days inpatient. If FL it is called the Marchman Act... similar to a Baker Act but for substance. You need to look it up in your county court system,,,, it may be called something different in your area. Also, having an intervention with your family and friends, letting him know how you all are feeling, what you see, and what you would like from him, and consequences you to his lack of actions to get help, such as lack of contact, no more helping him, etc.
But other than that, you need to let him hit bottom, and losing people in his life may be helpful to his reality. But that is your call... do what you feel is necessary.