Once my father got to be 70+, he preferred a stop in between (overnight stopover) rather than flying this distance through as a straight shot. That would be in Y/Y+. But in J with extra room and comfort, might consider the long nonstop. Lack of mobility and risk of clotting is much higher in the elderly, and joints get really stiff if sitting in one position too long. The long hauls are miserable for younger adults but really an ordeal for the elderly.