Read read read, it is the best thing you can do to be a support person to him. Nami is an excellent place to start and they have support groups all over the country for people that have loved ones with BP. Their info. 1-800-467-3589 www.nami.org
Other good websites:
http://www.healthyplace.com/communities/bipolar/related/support.asp
http://www.pendulum.org/
http://www.psycom.net/depression.central.bipolar.html
Some resources to get you started. Also, remember it can take up to two years to stablize. I was diagnosed a year ago, was not quite on the right meds and attempted suicide three weeks ago. I was in such a deep depression and lost myself. My doctor would not listen to me so as soon as I got home from the hospital I got a different one! Let him know he has to be in charge of his illness and be proactive in keeping it under control. I learned that from my experience this past month. Thank heavens my fiance found me in time and we are now rebuilding our relationship, but it was so trumatic that it is taking time. He is so scared, but I am so determined to never have that happen again. I created my safety plan and am on the right meds, for I am feeling more stable than I have in years! I have one more week before the medication really starts to take a steady affect. If you are up for the challange, it will get easier over time, just hang in there!
You say you just found out. Did he just go to a psych and get a DX? Yes the meds will help a lot if he stays on them. It will take a while for the meds to get in his system so don't expect to see an improvement overnight. Most will take 4-6 weeks.
He will still have mood swings, Heck everyone does. The meds will just help hold them in a more normal range although he could still tip into a manic or depression now and then. Nothing is perfect and if that should happen he will need to talk to his pdoc about adjusting his meds. Med adjustment is a life long thing. Our bodies get used to them.
His BP can get worse if he does not take the meds. He will prob. fight the meds when he gets stable on them and think he is "cured" and nothing is wrong. Denial is a typical trait of BP. If he can get over that and stay on the meds his life will be much better. BP can not be "cured" only maintained like being diabetic.
As to his back that is a separate issue. Nerve damage has nothing to due with a chemical imbalance in the brain. IMO