If that turns out to be the cause then I wish her well and hope she gets a handle on her medications and blood levels, etc.
As a cancer survivor who went through some very grueling chemotherapy I know first-hand about how bad chemo can be and how severe anemia can be in its effects..... I also know I never drove a vehicle while I was in chemo or for quite awhile afterwards, because the effects are too severe (there are milder forms of chemo, such as most of the kinds that can be dispensed in pills (I had to be hooked up to IVs for 6 hours at a time). I was never so disoriented as she seems to have become, but I would not have dreamed of driving with the chemo I had.....