Perhaps you can establish that this person is dead first. For example, this person can bring a flower and lay it on the grave...(Where does the monologue take place?)
Perhaps you might add a line...
Actor enters with 2 drinks....(Puts one on table across from him, and he holds the other) "I brought your favorite drink." I wished you were still here to talk to....cause I really need you right now! (Have him look up to perhaps establish that he is in Heaven) "I can really use one of your wise cracks."