Can you set up a shared google calendar? Then, when you add things to the calendar it can automatically send him an email (reminders, too!) Do either of you use smart phones/google?
Or... what if you (deep breath) validated him a bit... "I'm sorry if it seems like I am not keeping you updated. The boys love when you come to their practices. It seems as though our current system of isn't working as well as either of us would like. What do you think would work better? Maybe we can find a solution that works well for both of us?"
(Vets--how does that sound? I don't want to give bad advice. ..but I'm trying to practice some of this myself! )
