When I said that I would look on it more favorably that doesn't mean that I would necessarily agree with her breaking their agreement, but that I would be more understanding of the financial need in raising a child. He's raised now. College is expensive, but it is not an entitlement.
You are absolutely right that he could have filed for custody/visitation at any point, but he honored their agreement that he would have no rights ... she's the one that broke that agreement.
Respectfully, I wish to add that I am not so sure what their agreement was.
Since it is not in writing ... how do we know what was intended?
Putting all that aside..
As the legal father IMO whatever the child's age he should have paid support.