How do people make ends meet when the only income is aging parent's social security check because the caregiver has had to quit their job?

I've read several stories here where someone quits their job to provide full time care of a parent in their home. Thus, the most frequent question about how to get paid for taking care of a parent at home. I cannot get my mind around the idea that two people can live on only social security alone for I see how small my mother's social security check is.