I can't touch too much on the quality of a MSI laptop, because I have never used one or owned their hardware.
The i7 core doesn't mention how many cores it has. But the model number (3630QM) implies that it's a quad core.
The way I understand it, it works like this:
- i7 - Quad Core, HyperThreading.
- i5 - Quad Core, no HyperThreading.
- i3 - Dual Core, no HyperThreading.
HyperThreading gives 1 "software" based core for each hardware core. So you can think of this as the i7 actually having 8 cores (not really, but basically), which is what will show up when you look at task manager in windows.
The graphics card is said to be able to run Battlefield 3 on medium settings (not 1920x1080 resolution) well, and (lesser) games like Modern Warfare 2 on high settings. That laptop meets the minimum system requirements for COD:Ghosts. So you can imagine playing it on low-medium settings, maybe some other tweaks will make it ok.
I bought this laptop for gaming two years ago. I was able to play most games on medium-high settings. The nice thing about that laptop was the cooling system, which really made a difference. If you are going to let your brother game on that laptop, he will need a cooling pad. Not the silly 5$ walmart version either. Something like this should be better. The laptop I bought had better specs then my desktop (CPU, GPU, RAM, etc) but still my desktop performed better on games. The power and cooling is just more on my desktop, and sometimes the numbers on those chips just dont mean anything in the real world. Its almost a gamble!