I’d like to add Adafruit to the list. Breakouts of a different kind plus cool house-designed kits with communities around them. They’ve never done me wrong.
The Raspberry Pis also use a different processor architecture (KISS explanation- they work differently) than the processors most everyday computers, so it’ll give him something else to help learn on. Glad he liked it!
Old Raspberry Pis use a system with a 32-bit ARM core; newer Pis use a 64-bit ARM core, like a Macintosh. Actually, if you count all the different ARM processors, this is the most widely used processor architecture today, not different from most everyday computers. But unless you need to do some real powerful hacking you can just program it using any high-level language of your choice like C, Python, etc.
Well…
It’s only like 3 Macintosh’s - the ones with the M1 chip that were introduced recently.
Up until then, all Macs used Intel chips. iOS devices (iPhones, iPads, Apple watches) used ARM processors.
If you insist on living in the past, then I had some Macs that used 32-bit Motorola and PowerPC microprocessors 
(Never bought an intel-based one.)
The point of a package like the free Arduino IDE is, for a novice it is easy to get started with simple applications without (usually) having to worry about the underlying architecture because it runs a C++ compiler for you. The same is basically true for the Raspberry Pi, and you can find ready-to-use libraries to drive servos, touchscreens, displays, etc. If the guy is learning specifically about the ARM architecture then obviously it’s great for that, too.
I actually co-developed an Xcode-based cross-complier that I use to program my Raspberry Pi Compute Module - based embedded controller system.
Arduinos are based on the Amtel AVR family of microcontrollers. There are many other families of micro controller. The ESP32 are popular for home automation because they come with built in Wifi and Bluetooth built in. A combination of a Raspberry Pi to run a server talking to small microcontrollers with sensors over a wired or wireless network is a common design. Micro controllers use much less power than the ARM processor in a Pi and it is easy to connnect many types of sensors to microcontrollers.
There are very active communities associated with micro-controllers and small computer processors like the ARM in the Raspberry Pi. There is a lot of help out there. Both Arduino and Pi have strong educational support and there is a lot of books, magazines and forums intended to help people to learn.
I just bought this book for my nephew who is studying computing at university and needs to get a grounding in electronics and microcontrollers.
The author, Charles Platt, has a very effective ‘discover by doing’ style with clear illustrations that encourages experimentation and invention. Quite different from the dry academic tomes I had to deal with.
It is a very cool time to be studying electronics and computing.
It has always been a cool time to be studying electronics and computing.
The way it has been taught in the past has been very dry indeed, full of academic rigour that makes great demands on the student to learn lots of theory, which can be very discouraging. These days there are more enlightened approaches to learning through experimentation and just tinkering around with circuits. This opens the subject up to many more curious minds. The Internet has also allowed technical communities to share information and skills easily and the educational resources for learning are much improved. I find than way cooler than the prescriptive approach that tends to be the way of academic institutions. Though I guess it depends what works for a particular individual.
Didn’t go to school so wasn’t a problem for me.