Ruth died in the summer of '48, and of the last photos that I've seen of him he looked a lot less robust than he appears with your grandfather. I'd guess this is from the summer of '46 or '47.
This photo, for me, is as good as it gets.... Babe Ruth, IMO, was one of the top personalities of the 20th century. To have a photo of him with a close family member is priceless.
