Evening,
The one you have linked to is a pretty decent basic set up. The one thing I would say is the built in amp/mixer isn't always the best option.
If he gets to the stage where he needs to mic up the drummer properly, drum microphones are a great investment, but do need around 4-6 channels. You can pick up a set of drum mic's for around £100 and they do make a difference.
Obviously it does cost a bit more to get a separate amp and mixer. But at least it means it would (in theory) cost less in the future to upgrade.
Something like this – LINK TO EBAY isn't bad for the speaker set up. And then a simple mixer like this LINK TO EBAY
All depends on how much you are looking to spend.
One think definitely worth saying, is the system can be a good as possible. But you need to spend some decent money on microphones, otherwise its not worth it.
Hope that helps, let me know if you need any more info, i am more than happy to help.
Cheers
Josh,,,