It's hard anytime you can't take care of your kid. It's what any good parent wants to do, mom or dad. I can't speak for the personal relationships between your son and each of you, but I hope he can at least find comfort in your ex's care.

Also, more for my own knowledge, if someone is bipolar, but manic only, does the that just make them manic? That seems like saying a depressed person is bipolar, even though they only have depression.