In 2042, my sister was 40 years old and my sister's daughter was 16 years old. That 47-year-old man is the child's uncle, and that 5 1 year-old woman is the child's grandmother, right?
You can't tell whose child a person is by age, because some people are divided there, which may be very small, or they may become uncles, aunts, or even aunts and grandfathers. If an idle person is judged only by his age, if he is about ten years behind his mother, he will be happy at best and will not be a grandmother.