Normally, by LCN standards, a boss can make or break anybody within his Family. But this unusual set up between Castellano and Dellacroce, prevented Castellano to move on Gotti, at least while Dellacroce was still alive.
To a point.
Dellacroce COULD NOT have saved Gotti upon release of the Ruggerio tapes though.
Dellacoce ran his side to a point only. Paul was the boss and a disregard of the rules to such an end was well beyond Dellacroce's influence to save him.