As some of the comments suggest above the only real way to get a feel for a care home is to visit it and make close inspection. One thing which I've found is a major indicator of a care homes quality is their level of staff turnover.
If there is a large volume of staff turnover in social care jobs
(whether firing or quitting) it is a strong indicator that it is not being run to the highest standards. If there are nurses there who have worked there for a reasonably long time then it's likely that they enjoy their job and and it is effectively a well run operation.