The hope is that the kids aren't already infected, that seems like a very rare case. Sure it can happen, but they aren't yet recommending you don't even see family.
Many grandparents in the US live nearby and see their grandkids often and often look after them with some regularity. That seems to be the sort of scenario where they'd be employed to watch them while they are in learning from home situations, no? I don't think we are talking about frail people in nursing homes.