your son is in your care.
you control whether or not you raise him or give him up for adoption, and clearly you want to raise him.
you do not have to be married to have and raise a child, its just something that everyone has been programmed to believe in our society.
your dad cannot control this decision for you. and if i were you, i would talk to your counsellor about this, because he or she will be able to help you even more with this situation, and also talk to your friends mother too, if this does end up going to court, you will have her as a witness that you are a fit mother.
the people in your life who know you best, your friend, friends mom and counsellor will be able to help you get through this and support you as well.
your dad has never had anything to do with you, so why he cares now is a shocker. just brush him off and if you have to cut off contact from him, that is what i would do.
but talk to your counsellor and friend and friends mother as to what you should do next.
good luck hun, you can get through this.