"EDIT: just found some really sus guy then. Level E again... in 1 hour he uploaded that much? sure sure."
It doesn't need to be fake.
I got a 30/30 mbit, and will get free upgrade to 60/60 this month, and with the 30/30 I can upload ~3.6 MB/s, which means around 13 GB per hour.
New connection will mean around 26 GB per hour. If he got over or around 30/30 mbit, it doesn't have to be fake at all.
I'm not saying that it can't be fake, just that it doesn't have to be a stats-hacker to get 14GB per hour.