How about a joint session with your pdoc, who can probably describe the reality of bipolar better than anyone, as well as reassure them you can be responsible parents when you are stable? You could also get them literature from National Institute of Mental Health or some such well known agency for them to do a little reading or research.

I think sending your son over to his grandparents was a responsible thing to do. I also think it was probably very hard! Kudos to you for taking good care of your child!

If his t thinks it will be years before he can work, you might want to apply for SSD, get some added income.