No idea if he was boss material or not, but he wasn't exactly promoted to underboss due to his experience. Rather Stanfa wanted to make peace with the young guys. And I guess, joey Chang was the only capable guy who was friendly with Stanfa

Wasn't he given a pass and allowed to retire by the merlino faction, plus given his physical state I can safely say he had nothing to do with OC


Edit- Leonetti says how "heartbroken the father must be, and that he's a beautiful man, how hard it must be sitting there watching what was happening with his sons"

Just goes to show how much greed these guys have. They're willing to kill their flesh and blood just to gain power and ultimately the money that comes with it