well he can wait for his next paycheck and get a 7950 if he can.
Trust me if he want to CF that card in the future he needs 3GB Vram. BF3 uses around 1.5GB of Vram and in the next year or so, game devs will make a game that uses 3GB Vram. if he doesn't want to CF he can upgrade for the next card which may have 4 or 5GB of Vram but if he does want to CF then Vram will help him in the future to not bottleneck his GPU power. you can always add more card to increase your GPU power but you can't increase your Vram. so just to stay in the safe side it wouldn't hurt to get as much Vram as he can.
I made this mistake where I have 5970 and 5870 in CF and I only have 1024MB of Vram and because of that I can't use my GPU power and I'm being bottlenecked by my Vram.