What should be his first step?

I have a friend who’s son has recently become a father, but he has not seen the child and we’re trying to help her figure out the next step. He’s still young, 20-25, and there’s a possibility that the baby may not be his.
The history as I understand it is this:
Her family has alienated his family for a while so that when they married, his family was not present. They have not been married for even a year but she has kicked him out of the home. He went out after work with some friends, called and told her that’s what he was doing and when he got home the locks were changed. The family learned that the baby was born last week through social media and that there was a minor medical condition. The mother and child are at home now but she will not respond to his attempts to contact her. He has not been able to speak to her about their relationship or the child, what her intentions are, or what her expectations are. I do not think child support has been mentioned but her parents are pretty well off and may be willing to forego support.
I’ve told them he should call inform her of his intent to come to the home to visit the child and retrieve some of his personal items, and to give a date and time. To take a 3rd party with him that is not as close to the situation and could witness for them, this protects everyone involved, and not wait too long because that would set a precedent. I’m not certain he has the funds to hire an attorney at the moment.
Is there anything that he can do or has a right to at the moment? Would he be on the birth certificate since they are married? Can he contact the hospital and get the child’s medical record/birth certificate? Legally, where does he stand?

The only advice you can give him is to speak to an attorney. If she does not allow him to see the child, I would probably advise him to file a claim for child custody, but you should be careful giving him advice on how to proceed as you are not a lawyer and are not authorized to practice law.