As a doctor currently visiting tons (as in multiple dozens) of homes because of the pandemic (in Germany) and from my grandmothers I can echo the general sentiment: Staff usually care and the facilities are good but they're always understaffed.
All are expensive, but the best ones are not necessarily the best ones. The ones were turnover in staff is lower the relationship between caregivers and residents is usually better, but you can't go by size or beds to get an indication of that, word of mouth is best for this - unless you're a doctor and see in real life situations how everyone is treated without relatives there. However, it also very much depends on the old people. Some are impossible to keep tidy and content, even well fed and hydrated, be it dementia or stubbornness in people resenting the fact that they live there and can't care for themselves (or that their nagging partner is with them and did not stay at home 🥴). If someone doesn't drink anymore and pulls out IVs or their peg tube what are you gonna do, have them fixated at all times? Hospitals have the same problem, both staff wise and with more challenging patients, so it must not be elder abuse if someones grandma is smeared with filth and underweight, it could very well be that she was cleaned up minutes earlier, trust me. Of course stuff like unkept rooms and bad feet care can be indications, but even there you'd be shocked how unhygienic some well put together seeming people of all ages can be. There definitely are ones that are at least poorly run and not that hygienic, though, but the only instance of violence I witnessed was actually in the most renowned and exclusive one 😳
Even with all these caveats it is often the best option, though. Not always. That's why it always has to be a decision best agreed upon by everyone in the family and ideally involving social services and the primary care doctor - who usually has a decent grasp on local homes from my experience, since most here continue doing "house consultation" for their patients in care homes.
So get her doctors and your mother and your grandmother involved, look at the money side of things, see if the mental and physical strain on both your mother and grandmother is tolerable (and it IS straining for both parent and child once the roles reverse), see if live-in caretakers or a visiting caretaker are a thing around you and if the accommodation in your mother's place can be made adequate.
Personally I know that my grandfather really struggled with his conscience to put my grandma into a care home. Even with visiting careers it wasn't a fit place to live for her, though, even if he had promised her she'd never have to leave their house. She was so gone with her dementia she'd accuse him of breaking in and told what'd happen once her husband came home, lock out her caretakers, hide yogurt behind the space heater and eat it even if it went bad, fell repeatedly, kept drinking secretly, stuff like that. In her home she lived blissfully, holding hands with other people as far gone as her, told everyone she was a little girl and actually gained weight.
Long post, because seeing old peole quarantined with SARS-CoV-2 (and a year ago dying from Covid-19) is currently my daily bread and butter, so it's on my mind a lot.
