Hack Plumber? ... Oops -NO a licensed plumber!
At least he secured the piping. I would have used strapping to support it though. Things like this happen, even on big jobs. When i was working on the Boardwalk Hotel at Disney World, we found that someone had crossed most of the hot water lines to the tubs on the 4th floor. The worst problem was that the hot water was supplied by their boiler and a tempering valve was not installed in the domestic water supply lines. We had 200 degree water coming out of the hot water taps.
If you have never made a mistake, you haven't done much.