Frequently, in my talks and writings about the presidents, I have mentioned that John Tyler (1790-1862), who was president from 1841 to 1845, is the earliest president to still have living grandchildren. Tyler’s first wife — with whom he had eight children — died while he was president, and he married a woman thirty years his junior while he was president. After his presidency, Tyler and his second wife, Julia, had seven children. One of the sons from his second marriage, Lyon Gardiner Tyler, also married twice, the second time to a much younger woman, and had children with both wives. Two of Lyon’s children with his second wife, Susan Ruffin, were born in the 1920s, and made John Tyler the earliest-serving president with living grandchildren.
On September 26, one of those grandchildren, Lyon Gardiner Tyler, Jr., died. Born on January 3, 1925, he was 95 years old. He served in the Navy during World War II, earned a law degree and practiced law, and then in the 1960s he earned a doctorate in history and became a teacher.
With Lyon’s death, his younger brother, Harrison Ruffin Tyler (born in 1928), is the last living grandchild of President Tyler.
Lyon’s obituary is available at this link.