I read the most brilliant thing the other day... (I think it was one of heartbroken_kk's posts)
Just as someone full of negativity projects their behaviors on others, so do we project our goodness onto people who might not be deserving.
You have so much love and concern for your boys, and you can't imagine being their parent and not caring. You instinctively assume that he must have the same outlook, way way way deep deep down, and so you give him the benefit of the doubt and fill him in. That or you hope that it will inspire some kind of compassion in him.
Sorry. He's a dousche. Save that dime for yourself and your guys and go get some ice cream. (What, is this the 1920's? Jrazz = dork)