It depends a lot on which resolution you are expecting to play these games at. But for the most part the 260X lacks both power and memory capacity. Also I would go for 16 GB of RAM.
He doesn't need 16GB of memory, 8GB is fine for a low end system. The only reason to go above 8GB right now would be if he was doing workstation tasks, and spending a lot more money on a more complete system designed for those tasks.
snickersniff
You do not need the Thermal Paste unless you plan to add an after market cooler.