He bought it an it is really laggy on his computer even with the graphics set to low. Is there any mods or other things he can download/do to make it run better on his computer.

That is actually going to be a question that is better asked in the PC forum. I would think that your cuz has hardware and setting issues. Better to give the specs of the machine and go from there.

EDIT : This might be of some help for you both.http://www.gamesas.com/topic/1329260-b1gbaddaddys-big-post-of-fixes-and-tweaks/http://www.gamesas.com/topic/1329260-b1gbaddaddys-big-post-of-fixes-and-tweaks/

I know it is a hardware problem, his video card is not good enough. Mabye a mod that downgrades the graphics would work.

Tada...http://skyrim.nexusmods.com/mods/3890

EDIT : I know it doesn't increase performance...I just couldn't help myself...

EDIT 2 : Here is something...maybe...http://skyrim.nexusmods.com/mods/6387

EDIT 3 : or this...http://skyrim.nexusmods.com/mods/5123

I would start with just running at low settings, but I'm sure that is already in play.