I'm wondering if it's possible that the rehab facility is accidentally giving my mom medication?

My mother takes no medication, but is in the rehab facility to build her strength back up after a fall and pneumonia. Prior to the fall she could get around her home on her own, but now, can't get up or walk very far without help. When I go to see her at the rehab facility, she can barely keep her eyes open a lot of the time. In the past, when she was at home, if I woke her up when I showed up at her house unexpectedly, she bounced right up because she was glad to see me and would never let a nap interfere with a potential visit. She looked alert yesterday for the first time in a long time. Today she was back to "druggie-looking" eyes. It's so unlike her, it just occurred to me that maybe she's getting some medication that she isn't supposed to have. (Pretty much the whole time she's been in the facility --two weeks-- she has seemed very subdued and has had very little to say.) If this were a bad movie, I'd think there was a sinister plot at work.