Ducks ordered the hit on Buddy because Buddy, after his promotion to acting boss, tried to isolate Ducks from the family. Buddy was a fool who couldnt wait for his promotion to official boss so tried to sideline Ducks who was locked up at the time. What an ungrateful asshole who earned himself a bullet in the head for his foolishness.

Ducks was a good mob boss but he made the mistake of promoting two assholes in a row (Buddy and Amuso).