Eating problems - might be dental issues , has she been to dentist lately?
Has she given you medical power of atty? To speak with doctors?

But if she was setting a mix of meds and then none or cut back a lot, that could be why the changes in personality.

Maybe too someone is keeping her meds for their own use and not giving them to her?
I don't think a big change like that would have many other reasons ..

Might need to talk with the manager of the home to find out what is going on..