If there was an adjustment I don't think that it would be able to compensate for it going all the way to the floor. Can you ask the former owner what he thinks about the e-brake issue. imo, I would not think the brake pads would be worn down after so few years of service unless this unit was on the road a lot and had a lot of miles on it. imo, cable came loose or broke for some reason. cable should not have broken on such a new unit. If the brake pads have been changed, the e-cable may not have been put back on correctly. just know for now that you can not trust the the e-brake until the problem is found. Do the hydrolic brakes work fine and are firm?
2013 Forest River Salem Hemisphere SBT312QBUD
2001 CrewCab F-250 7.3 PowerStroke Diesel
SuperChip, BTS transmission, 6.0 Trans Cooler