How many care homes are there where the main language spoken is something other than English? Hardly any.
How many carers are there whose first language may not be English? A significant amount I should think.
Can you see the massive mismatch in numbers here? You might find a handful of carers, literally, who don't need to speak English well, who can deal with the patients and who have supervisors who deal with the world outside of their care home but out of the total number of carer jobs there are that has to be a tiny, tiny minority.
Those who don't have English as a first language can of course do the job but only if they learn a good level of English too. It is very useful to employ people who have another language but you can't do without the language of the country you are working in. Doesn't matter if it is this country or somewhere else in the world. I wouldn't go and work in France for example, and expect to get a carers job because although I can get by in French, I couldn't be trusted to know enough to work with vulnerable people who need me to get things absolutely right or have their lives put at risk. It would be too dangerous, even if I worked in a home for British expats. The home would be working within the French system, no matter what went on inside its doors.
Katese11 - I don't really call ironing or making tea a care job - I think you care confusing the argument by including that example. I think we are all talking about actual care work with patients, even the OP whose argument doesn't stand up at all.