He's convinced you're the bad guy because to him, you ARE the bad guy. He's not getting his way but you get to get yours... and yours DEEPLY impacts his life. He doesn't see the baby as anything but a choice right now so he doesn't understand why you would choose to punish him, when it would "set you free" as well, he sees it as a mutually beneficial decision. When you think about it from the man's point of view, it's easy to see it's "not fair" to him/them.
Whether he likes it or not, you could have aborted. You could have told him, you could have not told him. That choice was entirely your own and if he did know about the child, suddenly it's ripped from him. He can never carry the child himself, he's dependent on "a woman" to become a father.
Whether he likes it or not, you're having HIS child. YOU are deciding that whether he wants it or not, he is going to be a father. You could argue that he made that decision when he had unprotected sex, but he didn't. He didn't have sex with the idea of a child at the end. The OP didn't either but she is exercising her right to choose AND simultaneously taking away his right to choose (with 2 different opinions, someone was always going to "lose").
He is having a hard time having the control of that choice taken from him. Whether he's in the child's life or not, he is STILL going to have a child out there in the world somewhere. He is still, biologically speaking, a father.
All he sees is blinding panic that his life has changed forever, and there's nothing he can do about it. He is scared shitless and acting very badly out of fear. To him, he's involved in this never-ending car accident and he can't see a way out.
I know it's sucky for you right now, but his behaviour actually says to me that he DOES care about being a good father, and he doesn't feel that he can right now, or he's just scared. If he didn't care at all, he'd just leave and never talk to you again or give the baby anything.
You have given him so many ways out. In the child's life or not. No financial help, but it's still not enough. He's THAT scared of looking like a deadbeat dad he's trying his best not to be a dad at all.
He really needs someone to talk to him about his fear. His mother would be a good one but she seems scared to tip him over the edge. He sounds like he really needs someone to talk to, to come to terms with what's happening.
I would talk to him one last time and let him know that if he likes, you will stop talking him about it and you can just e-mail him, or update someone of his choosing (like his mum) and he can read or hear that information when he likes. That when he's ready to talk, you'll be here. That way he doesn't need to worry about hearing from you any more and he can comes to terms with things slowly.
I would also suggest to his mum that she talk to him about how SHE is feeling. That she's excited about being a grandma and that she knows that hurts him but that she will help however she can etc etc. Maybe hearing "I know you don't want this but it's happening" from his mum will help him.
Sorry this is so long!