You really don't want him around in the state he is in right now. I know it is hard especially for S but right now you just have to be the parents he needs. Accept that you cannot change H or will him into being a dad he will come around on his own terms. Not that it is fair in anyway but it is another thing you must let go. He will get through his fog and be a dad one day.
I've been through all these stages you're going through. I can't imagine how hard it is on you with expecting a new baby so please understand I am not trying to diminish that. However, it is in your best interest to not dwell on what he's not doing for S. It won't change a thing besides upset or anger you. This is what he's chose to do don't make it worse on yourself by beating yourself up over it. Let him be the man child.
