Being med-compliant can be a big struggle for some with BP and I would imagine being diagnosed at a younger age would make it even harder.
I will say that part of the reason I stay med-compliant is because I can't jeopordize my career, but another part of it is I feel my p-doc respects me and listens to my concerns. I hope you're son builds the same type of relationship with his p-doc.
I think your son is doing quite well for just being diagnosed. It will take time, but he needs to manage the illness you can't do it for him. He's very lucky to have you, but I'm worried you're going to burn yourself out, so please take time for yourself.