This is so, so, so damn beautiful. It just . . . it hurts in all the right places and it's so perfectly them, so dysfunctional and so painful and yet it works. The way you write Jack is particularly poignant; I can feel everything he's feeling. This sentence especially is just perfect:

His smile is soft, kind, surprised, painful. YES. That is my Jack.

I'm so glad that I found this! Now I want to read it again, just to drink it all in.