I am so glad he is doing well at school, Eva. A few ideas...
How about some cashews or other nuts for a protein snack?
My mom once sent those glow-in-the-dark star stickers and we put constellations on our ceiling.
DH's dad once made fudge and poured it into a lined poster tube, then sent it. We could not figure out what that heavy tube was!
Something for a hot drink, like cocoa mixes or coffee or tea.
One of the clubs at my college always set up a study break room in the library with crayons and paper, play-doh and other toys and that was surprisingly relaxing.
For you to be here now, trillions of drifting atoms had somehow to assemble in an intricate and intriguingly obliging manner to create you. It's an arrangement so specialized and particular that it has never been tried before and will only exist this once.
--Bill Bryson, "A Short History of Nearly Everything"