Lots of ways to approach this. Maybe go over some websites with him. Or have him go with you to your next appointment with your pdoc and have your pdoc explain it to him. In my case my sister did not understand my depression on being hospitalized. Could talk to her until I was blue in the face. After 20 years in abusive marriage, she madd a cry for help attempt on her own life. Now she understands. Maybe this is an illness you have to go through to truely understand. But I do not think that someone has to understand it in order to be supportive to help you.