This is where I've bought lots of stuff from, both for my self and on behalf of others. (Several other ABers have followed my recommendation and they've all given positive feedback). The quality of the products is excellent, as is their customer service:
https://accomputerwarehouse.com/product-category/cheap-refurbished-laptops-uk
However the laptop I'm typing this on at the moment didn't come from there, solely because they hadn't got exactly what I was looking for when I needed it. Instead I bought from this eBay seller:
https://tinyurl.com/4wbfv924
where there's 99.9% positive feedback after thousands of sales. Every laptop listed by that company is described in the finest detail, down to things like 'Missing Windows sticker', so purchaser's always know about any fault (even if it's only a tiny scratch on the lid) before buying. (Read the 'Condition' statement, at the top of machine's description, carefully to see what you'd be getting). Their prices are good too.
Chromebooks use their own operating system, Chrome OS, which has its root in Android. That means that users can't run Windows programs on their machine.
Cloudbooks are the Windows equivalent but both Chromebooks and Cloudbooks are based around the idea that you'll do everything 'in the cloud', often using online apps and storing files online, rather than having everything on your machine. That way of doing things might suit some but it's not for me. I'd rather stick with a conventional laptop.
One thing I would urge your pal to go for though is a solid state drive (SSD). They make everything VASTLY faster than when using a conventional hard drive (HDD).
This might meet his needs well:
https://accomputerwarehouse.com/product/15-6-laptop-8gb-ram-120gb-ssd/