Getting visitation advice

Okay, so my fiancée did a dna test an found out this little boy was his right after our baby was born. This little boy was already three at the time. The mom didn’t know if my fiancée was the dad or another man. And the mom didn’t let him know she was pregnant til after the baby was born. And ever since he’s been paying child support. We live 12 hours away so we can’t see him. We went to her state to visit his family a few times but she didn’t let him see him. So him and I were talking about getting visitation in the summer? But we didn’t know how to go about that because we live in separate states or if it was even possible for him to get any rights because he hasn’t been in his life. (Not his fault) but do you guys have any advice or input? That was be helpful. Thank you!