Yes, I know how you feel. My DH and I are nearly eighty and do not have major health issues just arthritis and blood pressure.
We used to meet our two GC's after school and take care of them until Dad came home from work.
We supervised homework and gave them a really good evening meal.
Now we have the same dilemma as you. I am sure children will come home after being in contact with many others and possibly be carriers.
Bearing this in mind, we both feel that the risk is too high at present, as if we contract the virus, we are unlikely to survive.
It is probably better to wait for infection rates to go right down.
Just our thoughts.