Mom and I have a good and trusting relationship. Occasionally, usually before I must leave for the evening before finishing our typical evening routine, she will do something she has previously known is unhealthy or not good, such as reusing a soiled washcloth, or trying to take the wrong meds. I admit, she does something that she knows is a trigger. Many of her behaviors are out of forgetfulness and they are handled calmly, with dignity. She has some age-related decline, but is generally pretty with it and I talk to her as an adult. I'm just sure she "tests the boundaries". What have you done in these instances?
Had your mother been evaluated, as in by a neuropsych with several hours of paper and pencil testing? You might find that mom has the reasoning ability ( nothing to do with memory) of a 5 year old.
That's what we discovered with my mom.
If you discuss things with her doctor, you might ask for tests to rule out some things and see if he has some input on it. I say this, because, when my LO first started with her cognitive decline, I didn't understand what was going on. She would ignore all hygiene measures and even stand fast in the fact that she had washed her hands, when she hadn't. You couldn't convince her that food would ever spoil. And, a couple of other things that were odd, but, I didn't realize what was happening. I thought she was being contrary. Later, it was quite clear as things progressed. I learned to ignore some things, (she can't help it) and address other things in a nice way and usually out of her sight. It may not be possible for her to handle her own hygiene and toileting.
With medication, regardless of why she's taking it improperly, I'd take over that task. It's too risky to take a chance on that, imo. It could have dire consequences.