When do you think it's safe?

My husband and I live 12 hours from our family. They were supposed to come down for our son's birthday but didn't make it due to their state shutting down. With things opening back up they keep asking if they can come visit, I haven't answered yet but I'm so torn. I don't want my son to get sick obviously but he hasn't seen anyone in two months and I don't want him to be isolated forever from fear. All the family obviously wouldn't come at once, 5 people at the most and they would be staying with us. What would you do? Or have you already?