If you want to fix things with her, you'd better find out what her plan is, and learn how to work your way into it.
He's still a kid - he depends on his family to support him through college. Therefore, he has to be on board with THEIR plan, not yours.
And yes, it sounds like you and his mom are having a power struggle over who gets to pull his strings. My crystal ball says SHE will win because she controls the money. And BTW - I am quite sure after investing herself in his welfare for 20+ years financially, emotionally, etc. she also wants what is best for him. She just may have a different perspective about what that is than you do.
Relax... I'll need some information first. Just the basic facts - can you show me where it hurts?