EX won't be visiting son this weekend

This would be the weekend I would allow EX to see DS but he is going to visit his sister out of town. The following weekend we are unavailable.

I am going to look at the calendar today and tell him which weekends he gets (first and third or second and forth) and if he misses his visit, it will not be made up!

Apparently its more important to see his grown adult sister that he can travel out of town to see at anytime (especially since he's not working) than to see his son for 2 hours. Keep in mind, he gets 4 hours a month - 48 hours a year...yes.....TWO DAYS....sad isn't it?