It wouldn't eliminate his ability to save a mafia. If he was the last alive, the effect of him having his own meeting originally or not would be the same. He could still select no one in the same situation, and should.
gor. his own meeting would eliminate his ability to save a mafia. He would only be able to target mafia to save at night.
In the event that he is last maf. He would conduct his own night meeting, but would only be able to select 'no one'. This keep town from obviously knowing he was Malprac if all other night role characters are dead.