That defies common sense. Send grandma away and let the young go on living. We can find a place for her or the other way around; let the young co habitat away from the high risk groups..
Where are you going to find a place for grandma?
Surely you aren’t suggesting sending her to a nursing home or retirement home. We’ve seen how easy it is to infect those places and then they are all goners.
How many spare empty apartments do you thing there are?
If every family has to split up by age and find new living quarters, there aren’t enough living places.