We tell mom that her parents are visiting her sister in another state and will call when they are home to pick her up. Is this a good idea?

My mother lives with me and my sister. She wants to go home, meaning her childhood home from 80 years ago. She says her parents must hate her since they haven't picked her up. We tell her her husband, my dad, is at work. Dozens of times a day, for the past year. I don't know if I can keep doing this. If I say her parents/husband are dead, she either says that i'm lying, or starts crying. Poor mama. She asks for my phone to call a cab to take her home. Is it ever a good idea to tell her her parents aren't living?