The average American consumes something like 40 lbs of cheese a year per the USDA. I can’t tell you how much a gallon of cheese weighs but it seems like it’s a fair bit more than 2 lbs each.
Gouda for him, though. However Brie his 15 minutes may be, let him enjoy it. 20 gallons over the course is not even all that much. That's barely more than a gallon a month. If you speak Portuguese, that's like less than 4 liters. A liter a week of cheese isn't exactly uncommon. That's like a few salads, some mac and cheese, a pizza, several cheese quesadillas, a box of Hungry Helper, and some cheese strings, plus cream cheese bagels, and a sprinkle of parm on the pizza. Who hasn't had one of those types of week before?
I just did the math, 200gal is 2664.5 fl oz (in freedom units) this means over 365 days hes eating 7.3 fl oz a day. 1 fl oz has about 50kcals so (ironicly) he's eating 365kcals of cheese