It’s not a monkey, it’s more like a sugar glider but even less suitable for a pet. Assuming her cat doesn’t kill it, which is just a matter of time, it’s far more work to care for than she will ever put in. On top of that, they cannot be kept singly so it’s already doomed. It will either have an agonizing, quick death (if the cat has a minute to play with it then finish it off before she realizes), or a very slow, incredibly agonizing death, bent over in pain, over a couple of days (as its little body succumbs to the toxic shock syndrome small mammals always get from cat bites, look it up). The less likely inevitability, if she somehow keeps the cat away, is it will start worrying at its own body as it has a breakdown for lack of social interaction and living alone in a cage, which means clawing its own eyes and ears apart, pulling its fur out, and eating its own fingers off its paws.
The worst part about this isn’t that she made such a dumb choice, it’s that this has doomed a whole lot more little marsupials to the same fate because Pekora just shined a beacon on a perviously nearly unknown exotic pet, which is like having a Super Bowl ad for your movie. Haato even sold out tarantula for food on Amazon. This will be similar.
Sauce: kept gliders and similar animals for 16 years, and helped run a shelter/animal rehab for exotic pets and former circus and petting zoo animals.
I also had 2 Savannahs myself (both died early of inherited genetic defects, a mother and son). Greatest animals I have ever seen but a lot more work than a typical cat or dog and not at all suited for most households.