So, just like I feared, instead of getting a reputable master plumber, Father went to some guy who's done repair work on the cheap for him many times long ago to buy and install the water heater.  To be fair, it now seems to work.  This guy also changed one valve from gate to ball, which is a good thing.  Unfortunately, however, another leak appears to have sprung from a different pipe, and this guy has to come back this morning to take care of that leak, as well as haul away the old water heater, which is still emptying itself of water.  So it's not really done.  I just hope this guy knows what he's doing.