Had I realised he was married or still with her, I would not have gotten involved, but thanks for your advice.

Then you did end up knowing what a POS he was and you're still involved. It doesn't exactly read well for your integrity either.

Did you read the legal bit? He doesn't need to handle it through the courts at all. He also gets to decide how the kid is raised, without a judge "clearing" me. She has not applied for any legal restrictions of me being around their child. I'm asking for advice to support him, I'm not trying to take action myself.

No, he literally does because she can hold him accountable for going against her wishes too. If he wants any sort of reasonable relationship with the mother of his child, he needs to respect her wishes or go through the courts to ensure his rights and make them enforceable.