A bottle of a limited release whisky, such as Ardbeg or Laphroaig should appreciate in value - have a look on eBay! And he could always drink it on his 16th...
When my daughter was born, I went round Manchester shooting several rolls of photos of the streets, shops, people, cars and whatever. I developed them (you could do it at home in the Black & White days) and sealed them in a film tin until her 18th. It went down very well, and she could have easily sold them, but still has them.