Bipolar Disorder & Manic Depression.

Is there a way to cure this or control it without the heavy doses of medication he's been prescribed by doctors? He's been living with it for more than 7 years now. Talks to himself sometimes, where he believes he's talking to a person. Makes life changing decisions based on alternate realities which to him is the only reality. Manic episodes with or without reason. He's a threat to himself - hurting himself, excessive speeding, taking risks with his own life. Emotional wreck. All the time. Does not cry - even at his own grandfather's funeral. Functions like a depressed individual. Inspite of all this. He owns a running business. Works 12-16 hours a day. Employees are happy with him. Family members are completely unaware. Lastly. He lives alone. So there's nobody to witness his behavior when he's at home. And has never agreed to take any medication or treatment. But I believe he will be open to any suggestions.