S.G.
I would let him buy her a special gift with his own money if he wishes, but he should give it to her outside of school.
I hear what Christy Lee is saying, but it is bad manners to give one friend a special gift in front of all the other friends (except if it is a birthday party). Adults wouldn't do that, so why should children. Can you imagine a get together with all of your friends and you give each friend a pen, and then say to one friend "I like you the best so I got you a watch."