After shopping around and running some test builds, at your current budget level you're better off buying a prebuilt machine. Below i've listed three that I think are good for him to get started, and offer room to grow and expand. All three of these would be good choices.
$799.99 - $1949.99
4K and VR ready, easy to open case for future upgrading. This machine has more options for upgrading at check out, giving a lot of choices. More money = better machine. Grab an i7 model if you can swing it, but the i5 models will be fine for a starter gaming machine. Lots of configurations available, these are good machines.
Another machine designed to be upgraded later, this is a great place to start. Specs wise these are about the same as the alienware above, but not as much configurability at check out.
Easy to open up to upgrade parts, but with it's small form factor you're going to be more limited as to how much you can upgrade it later. Still a good machine.
you can PROBABLY burn these files directly to DVD from the ftp location instead of having to download them at all. If that doesn't work, just transfer the files you want from the mapped drive to anywhere on your computer you want. Do it one file at a time.
How to do things