Test the young caregivers for antibodies. Only permit those with antibodies and no viral load to get anywhere near the elderly. Pay extra if necessary, it would be much better than breaking society.
The problem is that the problem of finding staff is difficult in normal circumstances, and almost impossible right now when lots of people are sick. Add to that the fact that unlike healthcare professionals these caregivers have much less hygiene trained and currently littlr PPE available, and you have the recipe for trouble.
Antibody tests are also almost useless on an individual level: If they have 4% false positive rate and 10% have antibodies then there are 36000 false positives (4% of 900k) when a million people are tested! Antibody tests are good at a group level to measure the progress of the epidemic, but unless the incidence is high or better test methods are found, they are near useless for what you are describing, sadly.
Antibody tests are also almost useless on an individual level: If they have 4% false positive rate and 10% have antibodies then there are 36000 false positives (4% of 900k) when a million people are tested! Antibody tests are good at a group level to measure the progress of the epidemic, but unless the incidence is high or better test methods are found, they are near useless for what you are describing, sadly.