If she has been using muriatic acid, she has probably already scorched the chrome. Look for a sort of gun blueing, run marks or ANY discoloration on the chrome, doorframe and drain. Make sure she sees it before you begin; photograph it.
You can use grout haze remover and a good stainless steel scrub pad. Take several. At only one week, the grout is still tender enough to sort of tickle off the tile, but be careful not to scrub so hard you leave dark marks. Common sense.
Promise a "whole bunch better", not perfection.