Hey Nick,
There are plenty of posts on the COW about hardware.
I am myself mainly using PC for work, except the odd FCPX job on Mac.
The specs that you are listing are IMHO far too low for professional work. If you are looking to go full in with the whole of the Creative Cloud.
My advice would be:
Minimum 64GB Ram.
1TB SSD drive for boot and Software + 4TB SSD drive for media etc.
NVidia is whatever you can afford, but try factor in one of their new ADA cards.
Processor; Intel is a good choice. But are you just playing back video, or will you be doing Compositing / After Effects?
As suggested, there are plenty of recent articles around – you’ll find that we all have different opinions depending on the work we do. But if your brother can build you something that is easy to upgrade, start out low, and upgrade when stuck.
Atb
Mads