I don't think there is much anyone can tell you about the cane that you don't already know. It was either used by Jacob in his old age or, if it's nicely carved and decorated, may have simply hung on his wall as a momento of his service. Your best bet is to find more info about Jacob's Civil War service. There may be something significant to the date, as it might be the 50th anniversary of an important event in his military career.

The cane I have, pictured here, is dated 1865. It belonged to Corporal David E. Jones of the 117th NY Infantry. It's carved with his name, rank, regiment, hometown, the battles he fought in, several corp badges, a patriotic shield, etc. He was wounded in the head at Fort Fisher on January 15, 1865. The cane may have been carved by (or for) him when he was in the hospital recovering from his wound.

JHG