I've two DC, one at primary one at secondary (well until today) both have had others off in their year groups and teachers also.
I have been enforcing the hand washing and cleaning at home etc, however I am beginning to despair of DH / PIL
Thinking do I just have to stay out now and leave them to it?
Situation is FIL mid 70s, lung condition, already very breathless on steroids and the like. MIL high blood pressure, 70s also
DH says it is 'up to them' if they want to see the DC. PIL usually come round on weekends, been avoiding last couple telling them I have a bug, but they still keep trying to come round.
What can you actually do though when it is his parents and they are all doing as they wish? It is so unfair on the DC, what if they give it to PIL?
Anyone else in this kind of situation? 
DH just says 'you deal with your parents and I will deal with mine" "They can do what they want' etc.
To top it off, DH himself has an autoimmune condition too, but doesn't seem to take this seriously.