In his advanced age Carter's mental facilities began to falter (due to a brain tumor which was successfully removed, and several falls), nevertheless he continued making public speaking appearances (though he was unable to attend the funeral of [[Billy Graham]], not due to his illness, but due to his wife's recent surgery) and worked with the scandal-ridden Habitat for Humanity program.<ref>https://www.propublica.org/article/how-a-tip-about-habitat-for-humanity-became-a-whole-different-story</ref> As of 2020, he was the earliest-serving of five living U.S. presidents, the longest-lived president (and the first to reach the age of 95), the longest-retired president and the first to live forty years after initial inauguration. | In his advanced age Carter's mental facilities began to falter (due to a brain tumor which was successfully removed, and several falls), nevertheless he continued making public speaking appearances (though he was unable to attend the funeral of [[Billy Graham]], not due to his illness, but due to his wife's recent surgery) and worked with the scandal-ridden Habitat for Humanity program.<ref>https://www.propublica.org/article/how-a-tip-about-habitat-for-humanity-became-a-whole-different-story</ref> As of 2020, he was the earliest-serving of five living U.S. presidents, the longest-lived president (and the first to reach the age of 95), the longest-retired president and the first to live forty years after initial inauguration. |