Treese, hope you are still on the up,

"Its funny how our children bring us together...we bring them into this world and they end up taking care of us in more ways than we think...."

This is soo true, my kids literally saved my life and I often think it has been a role reversal. My d sometimes sounds like my mum--she is older than yours tho.

As for this "I guess I still don't understand how someone who was so involved in his childrens lives suddenly changes and can go days without even talking to them..."
Treese you have to come to terms with the fact that you may never know the answer to this.
My x was a good Dad and thought the world of his kids, now he has no contact at all. After 8 years he saw his daughter 2 hrs, 1 son for half an hour and the other son not at all.
He got a text for his 30th birthday the first in 8 years. Do you think I will ever understand that-no. I gave up trying for the sake of my sanity and you must too.
Continue on your path, you cannot help him now.
I am pleased you are getting out, keep it up.