After this article I imagine he will get sacks full of cards. If you want to send one, the address is in the link.
http://www.foxnews.com/us/2018/05/1...-receive-100-cards-on-his-100th-birthday.html
http://www.foxnews.com/us/2018/05/1...-receive-100-cards-on-his-100th-birthday.html