Jenny, I'm so sorry you and your family are experiencing this nightmare. I hope that the support you find here on YLF helps. From what I've seen, this is an amazing group of women. I too applaud you for saying straight out that this is an illness. That will scare some people away, but it will also open doors to If you feel that you could use some support from people who love someone who has depression (as that appears to be at least part of your son's illness), you might try this message board. http://depressionfalloutmessageboard.yuku.com/ It may help you deal with the effect your son's illness has on you.
I do understand at least part of what you're dealing with. My husband has severe depression and anxiety and was rediagnosed with bipolar 2 a year ago. I've been to the hospital several times with him. To be honest those were some of my best nights of sleep because I knew he was safe. At the moment past treatments combined with the current combination of medications and exercise are working for him. I sincerely hope that the doctors can find what works for your son very soon.