SSDs are nice on DAWs, but larder sample libraries for audio plugins often preclude their use for everything. I'd use a SSD as a boot drive and for software installation, and at least a 2 TB drive for working files and sample libraries. 16 GB RAM is better than 8, many sample-library-based plugins can be set to dynamically use memory instead of streaming samples solely from disk.
With a firewire-based audio interface, as i mentioned earlier, he'll need a TI-based firewire card, preferably one that is PCIe based. IT will help with stability and performance.
If he is using REAPER, he may or may not need ProTools. Is he planning on using ProTools-specific plugins? Doing a lot of scoring for long-form video projects? Keep in mind that things are reversed from how they were a few years ago, its much more likely that a plugin will *not* have a pro tools version than it be ProTools-only. If he is using a lot of VST plugins, he'll either need a bridge for ProTools or to use ReWire to run them in REAPER.
please define 'light editing/rendering'... that can entail more hard drive space as well.