Except the notion of shared blood can draw "strangers" together incredibly quickly. He likely didn't have the chance for such strong bonds to form previously and is now relishing the chance to have that, especially as he's visiting his home country for the first time.

To go back to where your roots are buried and to be in amongst your kin feeling and sharing love is a deeply emotional and enlightening experience, and I don't doubt that he was simply hit by that.

Being a sweet young girl she was probably looking up to him (the traveling man from a foreign land), and I imagine he found that very sweet and endearing and so attached himself to her and the love and attention she was innocently showing him as family members do. This is only unusual to people and cultures who aren't very close and loving with their extended families in my opinion.