David Andrew McCoy (also known an Robert Edward Lee McCoy) (2183-2264) was a Human male who lived during the 22nd and 23rd centuries. He was the son of Thomas Jackson McCoy and father of legendary Starfleet officer Leonard McCoy.
Like his father, David earned an M.D. Either he never left the general area of his family home in Atlanta, Georgia, or by his mid-forties he had returned there, with his wife Eleanora, to raise a family. He eschewed following in his father's footsteps into academia and research, preferring general practice and family medicine.
In 2264, he contracted pyrrhoneuritis, a rare disease imported from colony worlds. Even at age 81, David had been wiry and robust, not even considering retirement, but three months after contracting the disease he had lost about a third of his body weight, was crippled, bedridden, and wracked with pain. The agony became so unbearable, overwhelming even high doses of painkillers, that he begged his son Leonard to turn off his life support machinery.
Tragically, within only a few weeks of Leonard McCoy's succumbing to David's agonized pleas and letting him die, a breakthrough was made in creating a cure, leaving the younger McCoy to blame himself for David's death for many years afterwards. In 2287, the Vulcan renegade Sybok forced McCoy to relive the act, finally allowing McCoy to deal with the feelings of guilt. After Sybok died, McCoy thanked his friend and Sybok's half-brother Spock for finally allowing McCoy to get past the pain and guilt of his father's death. (TOS novelization: Star Trek V: The Final Frontier)