Not thousands (I might save a big gift til he qualifies). I've actually gone with a set of insulated screwdrivers but he has Xmas and then a birthday coming up too so I'm happy for more ideas up to about £200 I guess?
The big-ticket items above £200 are probably best left until he has decided on features, etc, and needs it.
For £200 or so you are probably better with a couple of smaller but useful items.
@marconi suggestion of the C.K Automatic Wire Stripper is a good call for much domestic work as it does a really nest job of stripping twin-and-earth cable, only down-side is tends to bite your palms if not careful - I took an angle grinder to mine to remove the bits that bite and otherwise are pretty useless.
Obviously you should check what he as so as not to duplicate stuff! The Wera insulated screwdriver sets are also a really good call.
I would add that a proper crimp tool for common terminals is worth considering. While you can get better ones (e.g. Knipex at around x10 cost), this is a good minimum choice:
Tightly join two electrical wires using this latching crimping tool from Minotaur. It works by heavily compressing the materials to create a permanent bond. You can take your pick from three different settings, each designed for use with cables ranging from 0.5 mm² to 6 mm² in diameter. This...
www.toolstation.com
If you want to get something safety-related then this is an essential for professional work where you can prove your voltage tester is working before using it to check if something is live or not:
Intelligent voltage ramp testing for voltage indicators and multimeters
www.cef.co.uk
As for voltage testers, you get all sorts of options and folks here will have plenty of suggestions. I have this one and it is reasonably priced, simple (so little change of errors) and so far i have not destroyed it:
Excellent value LED voltage and continuity tester
www.cef.co.uk