Dear Abby: My close friend’s daughter is grieving her death. Should I tell her she was unfaithful?

Dear Abby: Last year, a lifelong friend of mine, “Lisa,” succumbed to long-term cancer. I’m close to her only child, “Becky.” About six months after Lisa’s death, Becky’s father, “Jack,” informed her that he had a steady girlfriend. Becky became upset, accusing him of being unfaithful as her mother lay dying.