Just tell her that since you have to do the big water change after a fishless cycle is complete, the water temp during cycling and the fish are really unrelated since the hotter water in the tank during cycling will almost all be removed and replace. I don't know if any tests have been conducted to see just how high water temperatures have to get before bacteria growth starts to slow but this article says that they tested up to 95 degrees and that the rate of nitification increased up til then.
