Why do many people say "Mom is at home"?

I have heard this sentence, but I heard it more succinctly: Mom is at home. Of course, it all means the same thing. I didn't quite understand this sentence before, but it was not until my grandmother died that I understood what a mother was at home.

My grandmother gave birth to five sons, three of whom, my uncle, accidentally fell into the lake and died when he was seven years old. My father is the youngest son of my grandparents. I once asked my father why my grandparents had so many children at that time. You were poor at that time, so the more children you had, the poorer you became. Dad told me that there was a saying at that time, called hero mother. The more children there are, the bigger they get, so grandma gave birth to five children. Because there are many children, my grandmother was in her forties when she gave birth to my father, and my grandfather was in her fifties. Now she is an elderly woman. However, my grandfather died at the age of 95, six or seven years later than my grandfather, and she was 93 years old when she died. My grandparents have lived for nearly a century. My father is the youngest son of my grandparents and the most filial son. My grandparents grew up in the countryside. My father took my grandparents to the city. When my grandparents are old, it happens that my father is capable. So in their old age, their father was very kind to them and lived a good life.

After grandpa died, grandma was alone and her uncles came to visit her occasionally. During the Spring Festival, they also know to visit my grandmother. Although they don't come often and only visit her once in a while, they also know to visit their mother. Later, after grandma died, my uncles basically stopped coming and were busy with their own affairs. My uncles only know how to earn money and don't care much about the elderly. I didn't come back until the holiday. I really can't see these uncles after my grandmother died. Brothers and sisters seldom come back and don't get together during the New Year. It's really that my mother is gone and my relatives have become relatives.