Condolence Thank You Cards I Want To Send A Thank You Card To An Old Neighbor. What Is The Best Way To Find His Address?

I want to send a thank you card to an old neighbor. What is the best way to find his address? - condolence thank you cards

My grandmother was a sympathy card from a friend of a friend. She knows the street and zip code, but not the house number. How to get it to send back a thank you card?