Perhaps he doesn't, not right now. I don't know, children are funny lol
My experience has been that even with parents you are close to, you just don't see them that often, don't always take their calls, don't always have time to chat.
Even right now I have several people I need to catch up with and I'm having a hard time juggling that and work and etc etc - and these are people I would love to spend time with. I have responsibilities. I have to go to the store and get some food (required), I have to get the brakes fixed on my car tomorrow (required!), plus all the regular day to day stuff there is to do. Plus he has a girlfriend, that takes up a lot of his time as well i'm sure.
It's a tough road, you know that. Getting through this is not easy, but you are. It takes time. Thing is your time is now about healing yourself rather than not. Eventually better days will outnumber the not so great days.