oh hun, its so hard and frustrating isnt it? My XH used to do this to my DS and soemtimes still does, his work (overtime) always comes first, then his social life, then DS. Its just so sad. I ended up doing the same as you, not telling DS that his dad was coming, just let it be a surprise if he showed up, it prevented lots of tears.

Yay for you fixing the screen door!