Welcome to our forum.
More clarification...there is a GFCI Breaker installed in the main panel and therefore all that is needed now is a disconnect to meet the 5 ft rule. But let me see if I can explain what my son is trying to do. His plan is to set the tub in a corner about 2 feet from each wall and take a measurement of the water when the tub is full (probably 36 inches) then measure up the wall from the nearest water point to meet the 5 foot rule. If my math is right, that would be about 7 foot from the ground, does not seem like a good idea to me.
Put the panel more than one foot of arms length horizontally from the closes edge of the tub. Install the GFI inside so that the elements don't render it useless since you probably won't test it once a month. Better safe than sorry.Steve