The position of Pope is not one in which there is anything like retirement. The Pope may become incapacitated, but he continues to fill the position while he breathes and can register his ability to communicate. Only when he is no longer able to communicate is the power of the Papacy shifted, even temporarily, to the regents within the Vatican. When breathing ceases the Papacy may be declared open.
Popes may abdictate, under huge pressure from the College of Cardinals, but they don't retire.
Speaking as the primary caregiver of an Alzheimer's patient (my mother, now deceased), I have to inform you that that approach has a serious downside risk.