Don't suppose he has got himself a new girlfriend recently has he? Not to be cynical or anything but there does sometimes seem to be a sudden interest in a child when trying to impress a new girlfriend.
Also it may be that his parents have put pressure on him as they want to know their grandchild. Do you have any contact with them? If so they may be able to shed some light on matters for you.
Also have you asked him why the sudden change of heart and if he is thinking of your child's welfare and needs or just his own wants? Remind him that your child has rights (which include having a relationship with both parents), but he also to be safe and secure. He has to work at the pace that suits your child and can't expect to be a hands on dad over night.
If it went to court and he pushed on with wanting contact then he would most certainly get awarded it. The court would order the contact, whereas at mediation you can (attempt) to agree it.
Presumably there are no concerns of violence, abduction etc? If you are happy for contact to go ahead in some form then list out what you believe is the way forward for you all with your child's welfare in mind.
Ask him what experience he has of looking after a young child and if he, as a concerned parent, would leave his child with a stranger who had little to know experience of taking care of a child.
Tell him to get himself a copy of birth to 5 matters and read it. Ask him to go on a parenting course. If he is serious about having contact then he will.
Ask him how, and also where, he intends to have contact? Court ordered contact will be little but often, so likely to start with an hour once or twice a week. In reality this means taking out for a walk somewhere close, park, library etc. Or maybe a structured play session at a messy club or sure start centre. Is he prepared to have his/your mother or someone you trust accompany him the first few times? Does he understand the importance of routine and what your child's routine is. He must fit around naps and meal times.
If he lives close by and intends to take your child to his home has he got the necessary stair gates, cupboard locks etc? He needs to do all this before contact can start.
You should also explain that bullying, shouting, and intimidating you will not get him what he wants. He needs to think about his child and what he needs and work slowly to building up both your and your son's trust and his relationship with his son.
Unfortunately absent fathers who have no experience of the reality of looking after a child tend to have no real understanding of the concerns and think a child will simply fit in with what they want. It doesn't work like that and he has to show he is prepared to do what is necessary to build a relationship. If he's not prepared to do that then he can go to court and find the court will tell him the same thing. If you can avoid court I would recommend doing so if at all possible. But if he won't listen and is determined it may tke that before he starts to listen I'm afraid.