As for asking for it back, seems that it is already in use. A gift is a gift, and parents should be the ones to decide if it is good for the kids. They should have said something at the time he got it.
I wouldn't ask for it back. But seven years old is just a little bit too young, to my way of thinking. All he should have, if anything, is a plain vanilla cell phone, if that. There's no reason for a small child to have all that expensive electronic equipment.
Is he in a school so bad that he has to walk past dangerous neighborhoods? Does he have to call 911 often? Or do his parents just want him to keep up with the Jones family?