You said he practices diligently.
The same goes for my oldest. Sometimes I feel that our children are better learners than us, at least than me, not just because we make time for them to practice and we offer them the appropriate enviroment, but also because this is how THEY want it, this is how they like to do. I see them as models in learning. They know how to have fun, how to focus and be more relaxed than me.
Either it's your dear Jacob, or my son, or any other child here, I really feel very much respect for them in such cases.
Way to go, Jacob!