This is a topic I haven't seen discussed much. A few SCs had grandchildren in their 70s when they were still alive, but I wonder what the record might be.
I recall Elizabeth Bolden's grandson being 74 when she was 114, and while writing the LQ biography for Marie Andersen (1909 - 2020), I found that she became a grandmother aged 35 (her daughter was born in 1928 and her grandson in 1945), and he was 74/75 at the time of Andersen's death.
Is there anyone older?
When Susana Lynn (1888-2001) died, her granddaughter Lula Mae Jackson (1917-2018) was still alive at age 83.
@heatwave116 I believe that Lynn was older, childbirth at 12 seems unlikely. Unfortunately the 1890 census was destroyed.