Can children with bipolar grow up to be self reliant or will they always need adult supervision?

My stepson has been diagnosed with bipolar, adhd and add. He is 14 physically but mentally (or perhaps socially) 8-10yrs old. His father is in denial about it and I don't know much about any of it. I just wonder if we need to sock away $ to take care of him his entire life or if he will be able to sustain himself. His Mother is bipolar as well and has numberous health problems. She is trying to state that she would better handle him because she understands his problems. Any thoughts ?