My wife was driving today and brakes started grinding.

I know these are heavy vehicles, and I live in hilly North Van, but that seems absurd that they are worn down already.
One note, braking has always seemed sluggish, compared to other vehicles I've driven. Also, lots of brake dust on the front rims, none on the back rims. I put it down to different pads when they were replaced by Japanoid, but now I'm wondering if the rear brakes are working at all...