Yes, but the question was could he get his flight review in his
amphibian if the amphibian was incapable of landing on the water. I see
your point though. I guess he could get the flight reveiw in a land
airplane and then still have privileges on his Seaplane rating with no
seaplane demonstration.

As for the instructor giving instruction in a Seaplane, I am not sure
but I think there is an exception for this one. If so it should be in
the FARs.