We know that he was alive 38 years ago, because Sengoku essentially mentioned him as being alive, as he joined Rocks back then. I’m sure the majority of people would agree that he wasn’t younger than 12 going by that silhouette, so he’s at least 50. Maybe you could make a compelling argument that he was a teenager 38 years ago, but it would still likely come off as a big stretch. Maybe 18 at the realistic minimum, so on that basis, he’s at least 56. I’d definitely be willing to believe he’s in his 60s or 70s too.