I would imagine Sofia would be more tame with Gustavo and would feel safe towards him, he seems to be genuinely a nice guy and would never in any way harm Peppino (Unless Peppino upset him-) So she's assure her little brother is in safe hands
As for Maurice oh he'd be so scared shitless, oh no That guy is gonna be a part of the family!? Now he won't be able to bully Peppino as much even without Gustavo around Peppino would tell him and would get an ass whooping in the next day lol