Miss Manners: My son won’t speak to us after we refused to care for his sick child

Dear Miss Manners: We had arranged with our son and daughter-in-law to babysit their 1- and 4-year-olds so they could go to an out-of-town concert, being gone for two nights. Three days before we were to arrive, the 4-year-old got sick and they took him to urgent care.