He’s not proud. He’s never one to bask in reflected glory. So he lets her think she does all the important educational stuff: her help with their homework, the after school clubs, the parents’ evenings.
But everyone knows it’s actually his singing that makes all the difference.
“Did you ever know that I’m your hero,” he sings to them every day. “And everything you would like to be.”
It is beyond doubt that this is what’s going to secure them good results. They don’t need to show or tell him. He can see what lies behind their slowly shaking heads.