I agree with you that john gotti killed the guy to save face since the the mafia you can't let a guy who kills your son walk but I don't think gotti ever felt he was forced to do it. Gotti knew exactly what he wanted to do to Favara the second he learned about his son's death. Gotti knew he couldn't do anything right away since the fbi were waiting for him to do something to favar so he waited a few months then took a vacation to florida in order to create an alibi