Well, not really a messenger. In his youth, Pierre Marco used his abilities to gather every bit of information he could find on all the families. Nino could be like that. A spy of some sorts.
Also, it's to your preference if he is adopted or associated.
We can liken Pierre Marco to a spider right, weaving his little web of information etc. However, due to his old age, his capabilities are limited already. So we can have Nino do the majorit of legwork for him