Since this is not for your own child ... the two best criteria to try to meet for a present are "loud" and "messy." If it's both, you really win. If there is a paint spinner set that makes fart noises, you will be thought the best auntie in the whole world ... by the kid. His parents will hate you forever, and not allow you to ever buy anything for the child ever again.

Something with wheels and/or low yield explosives will satisfy any male in this age group.

pokemon, yugi oh, magic cards? star wars figurines. heelies. slot cars. train set. bongos. art supplies. metal detector.