I would not share YOUR calendar with him. Point him to the source where YOU get your information. If it is from the school, give him the school phone number/website. Make him do the work in figuring out when the kids have stuff. F him when he wants you to tell him. How can he miss a valuable contribution of yours to the family (keeping up with the kids) if you keep giving it to him. You seem to have no problem finding out the kids schedules, he should not either.
Anyways, thats just me....
Me: 42 W: 32 Married 7 years together 8.5 S1: 7 S2:7 Bomb #1: 09-16-13 Recon #1: 11/13 A discovered 04-03-2014 W filed D 05-19-14 but never served me I filed D 12-02-2014 S 05-31-14 Divorced 5-19-16