> your sick, immunocompromised grandma.
I suggest being careful with your healthy grandma, don’t wait H’V until she gets sick. For one, under mild conditions, you can be in N95 and the grandma may enjoy your visit without. As in Bava Basra – when 1 roof is higher than the other, the top one has to build the wall not to see the lower one. In Roman/British/US law, the lower one would have to protect yourself.