Bob's neighbor Dave is good friends with Bob and cares for Bob who is old, sick and dying. Dave takes Bob to the grocery store, to the barber, run errands for Bob, and pays all his bills since Bob is bed ridden and has a difficult time getting around. Dave maintains that Bob had promised him his two gold rings worth ten thousand dollars each upon his death. However, when Bob eventually died, his son took his rings as part of Bob's estate. Dave claims the rings were promised to him and asks you as Judge to rule on his claim. How do you rule?