Yes, I agree with @janiemiranda , tell her as nicely as possible. Maybe preface this with something like “I would want to know if this were me so her goes: …” It’s possible that she isn’t using enough detergent and maybe taking her clothes out of the dryer before they are completely dry (causing the mildew smell). Maybe she can’t afford laundry detergent? Maybe she is clueless on how to do laundry? Maybe there is something dead in her drawer? (yuck). Anyway, good luck and believe me, she will be embarrassed but she will thank you for it at some point.