GFCI on sump pump circuit?
High On Safety

First, your neighbor is "goin' crazy for safety".  Being far from city water, one of our facilities has a Caterpillar diesel fire pump. The pump intentionally has no trips for low oil level, pressure, water temp or water level.  That's because you don't want dueling safety systems - don't want to trip to save the fire pump only to lose the warehouse. 

So your neighbor is like "I gotta shiny new safety toy, and Im'ma put it on everything."  Whoa there, Nelly.  GFCI is a safety system.  Just like the fire pump, you don't create dueling safety systems.   contradict another safety system's functioning.  Safety systems include refrigerators, radon systems, fire alarms, fire pumps and yeah, sump pumps.  

That is not to say one should completely ignore the risk of electrical shock. You should certainly make full use of other methods to ensure the safety of the sump pump.    The traditional method of ensuring all current-carrying conductors are encased in grounded metal, guarantees that wayward current cannot reach a human without reaching grounded metal first.  A milli-ohm path back to source assures an instantaneous breaker trip.  

The use-case for GFCI is ungrounded 2-prong portable appliances, particularly those dropped into a sink full of water connected to the water supply via plastic piping.  Putting one on a grounded refrigerator is absurd. 

Now, there is another rule which calls for GFCI protection for receptacles in any basement area.  However, that rule is based on the fundamental premise that anything and everything will be plugged into those receptacles.  Many AHJs will grant a waiver for single receptacles (1-socket) dedicated to a single appliance for which GFCI protection is not appropriate, and labeled as such.  In my view there should also be ample other sockets right nearby, so there is no temptation to borrow that socket or put a splitter on it. If the AHJ is not tolerant of that, I would simply hardwire the appliance, which utterly eliminates the "receptacle/anything" issue altogether.  

Do not use GFCI receptacles.

OK, that's a little harsh.  I'm trying to break you of the idea that GFCI is a receptacle. Actually,  GFCI is a "little black box" that protects downline loads.  Obviously, a GFCI recep protects its own sockets, duh.  However it's possible for any GFCI device to protect any other points-of-use attached to its LOAD terminals. On the other hand, over-use of LOAD is a nightmare for the careless.  Because of that, nothing should be ever connected to LOAD unless what that is is known. You don't want a GFCI reset to be in an improbable and unexpected place, though labeling helps that a lot. 

Note that proper labeling is mandatory when protecting downline receptacles. They must say "GFCI Protected [ / No Equipment Ground ]"  They should say "GFCI Protected - Reset in Hallway".  You can custom-make those labels on a P-touch or whatever; you don't have to use the blue ones.