Why would you been more drunken in a pressurized cabin than on the ground?
Yes, that is a common myth. There is no difference in a pressurized cabin.
Is 64 beers in 5 hours possible? Yes (especially if keeping them all down isn't a requirement), but he'd have to bring them aboard as there's no way you would or could get served that many. Hand-carrying 3 cases of beer on a commercial flight would exceed the standard carry-on size requirements... I call BS