...There aren't any actual Critical Fumble rules in 3.5.
They are actively one of the worst things ever.
Never, ever, EVER muse "out loud" about how Crit Fumbles would affect a given feat, especially one like this one, which is pretty obviously not for a serious game.
Why shouldn't you?
Because damn it, you're giving bad DMs ideas. And that is never a good thing.
Because, you know what? Auto-missing is already bad enough. Making a warrior drop their weapon because apparently they have the coordination of a drunken corpse is literally just kicking a man in the nuts after you punch him in the face.
tl;dr: Critical Fumbles are a house rule at best; the only effect for rolling a 1 on an attack roll is a miss.