Need Help with slow wireless

Ok so here is the deal. I set up static ip at my parents house when I was down there like 2 years ago. I assigned each computer and xbox an ip address. my brother got a new laptop and i did the same. He is having problems with wicked slow internet. But as soon as he goes somewhere else it works fine. He has friends that come over and theirs work fine. Its just his computer in our house that is getting really slow internet. By the way its a Dell 1525 with built in wireless and its a linksys rounter. No problems with any other computers in the house and another desktop that is on wireless. Im too far away to go and look at it so im trying to trouble shoot it from here. Anyone have any ideas. I would appreciate it. thanks

He gets internet fine when he connects hard wire. Its just wireless for his laptop only. His friends come over and they get great wireless internet for some reason his wireless internet is pretty much unusable like 5 min or so to load a page. Worse than dial up and its cable internet. Im out of ideas cause when he goes to a friends house it works fine. Its just my parents house with his laptop. it doesnt add up

Thanks, I forgot about that. Ive never had a problem with the channel before.