If the diver is experienced at that kind of work it should be easy.
Have a long-handled wrench handy so the diver can get enough leverage to free the prop nuts. When my diver replaced my prop the 18" pipe wrench I had on hand made his job easier.
If the diver is experienced, he will have the neccessary tools. In any event, it is not a particularly difficult job and there is no reason to haul the boat to change out a prop.