The first thing you need to do is try to observe the things your grandpa has been doing or the things that interests him. Is h into gardening, or perhaps fishing? Does he spend more time reading the newspaper or taking a nap on his favorite chair? You may want to choose a gift that is associated in the things he always do. You may want to give him seeds he can plant or new gardening tools. You may also want to give him a new fishing vest or a new durable fishing rod. For grandpas who love reading, you may want to give them books of their interest. You may want to check first on their collection to determine the particular books he reads. You can also try surfing for personalized gifts for men.
You may also want to read a few blogs or books about people turning sixty and the things that they often do to get some ideas how to make him extra happy.