What resolution are you gaming at? Are you using or planning to use multiple monitors? There's a report that nVidia is dropping prices in November to compete with AMD also.
http://www.tomshardware.com/news/amd-radeon-r7-r9-nvidia,24453.html
I think the CPU is fine. Look at costs. For him to switch to Intel would be the price of a new CPU and a new motherboard, and for what? He'd still be looking at the exact same graphics card, and for a whole lot of cost, and not really be increasing his frames per second.
Once he replies with what resolution and whether he's single monitor or opting to go more, we just can't say confidently one way or the other about adding another GPU.