At which point the family or social services step in. NOT when one of them is symptomatic and the other not. If only the wife was symptomatic, DC could easily have driven up to Durham to drop the sprog off and then driven back to London to look after the missus. Or, more rationally, one of the nearby London relatives picked the kid up.Given that the virus is generally understood to be unpredictable in terms of severity, how can you be so sure that two parents would be in a fit state to care for their child?
What part of that are you having difficulty understanding?