I understand what it's like to have depression and anxiety. I have experinced symptoms since I was 13, I am 30 now. Everyone who has these issues experinces them differently, so it's so hard to know what the solution for your son is. I have been taking anti-depress. and anti-anxiety for about 6 years now. At first I took the anti anxieties 1 or 2 times a day. Now I only take them once or twice a week. It took me 3.5 years to find a anti-depressant which worked for me and this time was never easy experimenting with different combinations or trying one which seemed to work, but then made me worse.
I have lived on my own since 18 and not had much financial or emotional support from either of my parents who themselves have had boughts of both anxiety and depression. I have worked and went to school for those 12 years away from home and it has not been easy due to my sickness. What helped me the most was challenging what I thought I could not do. I never thought I would goto art school, I did, I never thought I would goto university, I graduated with a double major in psychology and sociology with a A- average. I never thought I would learn and grow so much and learn to like myself much as I do so there is hope!
Taking psychology helped me to better understand what I am going through and about what I should expect from my doctors. Doing art helps me express myself and I love music too! I finished school and have only been out of work for about 6-9 months one year after I had had what I called my "nervous breakdown" It's tough to get out of bed when you feel numb or feel so down you feel as if you can't move....
What I would suggest you to do is slowly add things to your son's life which he enjoys like his music. Make it a regular thing he can look forward to. Do you have a pet? My dog was a life saver for me, they love unconditionally and they certainly give you a reason to get out of bed, or else you have a mess on the floor if you don't get up and take them out. Another thing I would suggest is volunteer work. Less pressure, but still it will get him out with people doing helpful things. I also suggest exercise, which has been the hardest for me to keep up with, but walking my dog started it, now I go to the gym too and the rush from your adrenaline starts about 10 minutes into your work out and this helps with depression.
So that's what I have to offer for advice. Get him to do things like odd jobs around the house which require some responsiblity to get him on the move. Little changes will make a difference hopefully! I really think Dr Phil shoudl do more show on depression and anxiety, especially since it is so common in our time in our society. Best wishes to your son and your family, PS another thought on helping is for you to read books on the topic and be open with him about what you learn!