Old age is an ordeal, of flesh and mind. Of winding down, of slowing down, of dying cells. It's accepting the loss of physical attractiveness and replacing it with the power and wisdom that can only come with old age.
And gradually his memory slipped a little, as memories do, even those with so much love attached to them; as if there is an unconscious healing process within the mind which mends up in spite of our desperate determination never to forget.