Because there is no such thing as a code for minimum showerhead height, you can install the showerhead anywhere you like. It is this height that normally dictates how high a shower wall runs with the preferred method running the wall tile up until it covers the showerhead, and then finish the wall at wherever the next full tile terminates above the showerhead as it sits on the wall.
The average showerhead’s height is 5 feet above a typical bathtub’s edge or 7 feet off the rough floor. This gives sufficient room for the average individual to comfortably shower. Unless you have a low ceiling where the termination point looks awkward, most tile showers terminate at the 7-foot mark on the wall, or wherever full tile falls close to that.
Disabled showers can have the tile installed on the wall however high you think they should go. You only need going a foot or so beyond the showerhead’s finish height allowing water spray to be captured by the tile, and not the drywall. If you want to keep a uniform look you, go to wherever full tile stops between 6 and 7 feet, regardless of how high the disabled showerhead is installed.
If the wall has a showerhead that terminates somewhere close to the ceiling, run the tile all the way to the ceiling rather than terminating on the wall. Otherwise, you are left with only a few inches of empty space.