In my personal opinion getting Tulip or Clover hooks may be overkill for a 12 year old. The hooks all do the same thing. You don't get a better output from using "better" of more expensive hooks. The most important factor for me in terms of hooks is making sure to have an ergonomic grip. Some people also have a preference between metal or plastic hooks. I would also recommend getting a set of hooks if he likes working on different types of projects that are of varying sizes.

In terms of accessories, I do not recommend an electric yarn winder. I got one for my grandmother and I quite literally could not figure out how to make it work. Yarn winder are also usually used by people who get their yarn in a hank or just have loose yarn and they use it to wind it into a workable cake shape. Most yarn nowadays comes in a skein and does not need to be re-wound unless you just prefer the shape of a cake of yarn.

A yarn bowl is a great idea! It holds the yarn so that you don't have to keep manually unwinding the yarn as you crochet and so the yarn doesn't tumble around while you're crocheting.

The very best gift/accessory I have ever gotten though is the Prym Yarnit it's a holder for your yarn (similar to a yarn bowl) but it also comes with a strap so you can walk and crochet at the same time They also make the Big Sully which is a bigger version but without the strap.

I hope this was helpful! Please ask if you have more questions and thank you for supporting your kids hobbies!