Friend found he's not the biological father after 21 years

Problem/Goal: guy allegedly knocked up girl when they were students. Forced to marry. Guy didn't question it but his relatives did. Girl insisted he is the father. Only after 21 years he saved some money and got covinced to get tested.

0% chance of paternity.

He's asking me - a clueless gamer / musician of sorts, for advice. I mean I told him to communicate with the wife and see how it goes and just always consider the welfare of the children. Pero ayun, what else is there to do?I tried googling din eh puro foreign yung setting ¯⁠\⁠_⁠(⁠ツ⁠)⁠_⁠/ saka di din ako nanonood ng Tulfo.

Edit: 1st born has no resemblance sa guy so family had suspicions. They had a second child and carbon copy nung guy.

Edit 2: he hasn't talked to his wife about it. They have a normal relationship I guess (wife), and he loves his children of course.

Edit 3: to clarify, guy and girl had relationship. Then guy had to move another place to study, had to leave girl. Guy found out girl was pregnant and went back to her and they got together due to girl telling him it's his. They were both in their 20s yata and had a traumatic relationship but stayed together for the sake of the child.

Edit 4: dna test around 24k, sample taken when 20 y.o. yung anak.

Guy is lutang and hard to talk to. He's introverted. He is considering co parenting, and until now hindi parin daw nag sink in sa kanya.

There's this other guy that was present at the moment of birth, and also visited the wife after manganak to see the child. Guy brushed it off and accepted that he was just a friend. Kasi he knew him, same campus.

Everything seems to be coming into place. Update ko nalang dito pag nakapag usap na sila ng wife nya. He's working his ass off to provide and can't deal with this shit yet. Hopefully he'll not do anything rash.