I would start by giving him a reason to work, such as "starting next month you will be paying $450 a month in rent." No matter who I am talking to, if they are not engaged in physical activity (working out) or a sport, they should be. Exercise is the best cure for depression, it ups the serotonin levels in the brain. While this doesn't work for everyone, it does work for most people. Sun is also useful for depression. Many people who were career drug addicts crash into depression when they are sober. It's the inability to deal with life's challenges that spur the drug use, to begin with. At 28 he has most of his life ahead of him, it's time to live again. If you are in good physical condition, start taking him hiking, tell him you want to go but don't want to go alone. Get him moving.