[DAF]

You are welcome! By-pass piping for WH's used to be optional years ago, but now it is pretty much standard. In my Innsbruck it is right behind the WH (inside the RV) and accessible from under the main bed. Tell your brother to look again inside the trailer in the vicinity of the WH for access. It can be in a storage compartment or even behind a detachable cover. If he now has hot water it means that the by-pass (if it exists) is off. You only use the by-pass when winterizing the RV so that the antifreeze does not go into the WH (expensive). All you have to do then is drain all the water from the WH.