Welcome to the Disney Parks Moms Panel, Daniela! You and your nephew are going to have a darling time on your adventure through the parks! My mom took my son to
Magic Kingdom for me one day when I was attending a conference a few years ago. They got into plenty of mischief and came back sprinkled with Pixie Dust!
During my first trip with my son, he was only three years old and I used my fingerprint to scan him into the parks. As he has gotten older, we’ve encountered the same issue as you: changing the fingerprint associated with the band. As my son grew up (I suppose we didn’t visit Neverland enough!), we approached the turnstiles and mentioned this to the Cast Member present (before we scanned). Using a iPad device, they signed him in, and asked us to them touch the pad in order to change the fingerprint associated with the account. Once my son was 5, he was old enough to sign in with minimal supervision and use his own fingerprint. I did tell him to always use the same finger, showed him how to hold still, and to learn exactly when to place it on the glass, but it only took a few entrances for him to get the hang of it.
After your first swapping of fingerprints, it will be easy to trade him off between you and his mom, and you’ll be off for fun. If your very own fingerprint doesn’t scan, you’ll find those same Cast Members will assist you at the turnstiles. As for that Pixie Dust, step into
Castle Couture in Fantasyland and ask the Cast Members there if anyone is handing out Pixie Dust for the day. You may get to make a wish and leave with more magic than you came in with! Please let me know if I can help with anything else for your magical vacation! ~Lindsey P.