True, pre-employment drug tests are fine under ADA, but I don't think that has much to do with disability, it's more to determine if a candidate is taking illegal drugs. I don't think they would report any prescription drugs as long as it's disclosed to the drug testing facility that there's a valid Rx. With some employment, a pre-employment physical is also required (ex. truck drivers) because certain conditions would disqualify them from driving. (high blood pressure, epilepsy, poor eyesight etc.) That's not discrimination, it's a safety issue.
Yeah, I doubt she's changed much since