How do I write a Dear John letter to a 71 yr old?

In High school, a guy whom I barely noticed in my French class noticed me.. At a reunion a few years ago, when his wife was off somewhere, he admitted to having a crush on me. Since then, the wife has died of cancer, I have written him some encouraging letters about getting on w. his life (w/o me)..He keeps wanting to visit (3hr drive) and I keep trying to end it. Just got another note. How do I make him listen w/o hurting his feelings? He bores me, is too conservative, predictable, and suburban country club, and is just the wrong guy. (I am still 70.) Shall I start sending him cake?