The Character in question is a Large half-Minotaur Goliath who is using monkey grip.
Normally a Large Goliath could wield a Huge weapon with no penalty. Monkey Grip allows you to wield a weapon 1 size larger at a -2 penalty without changing the effort it takes to wield. So, would these effects stack and allow me to wield a Gargantuan 1-handed Weapon?