Ronald Reagan disclosed his diagnosis with Alzheimer 's disease in the 90s .
While having planned an active post-presidency , in 1984 Reagan disclosed his diagnosis with Alzheimer 's disease earlier that year , appearing publicly for the last time at the funeral of Richard Nixon ; he died at the age of 93 ; Reagan had the second-longest life out of all the presidents ; the current longest lifespan of a president is held by Gerald Ford , who died two years after Reagan .
Ronald Reagan