Well, the ring search was a bust....couldn't find it after four hours.
Turns out that he thinks he might have dropped it in the house, so I also searched the vents with an endoscope I have, but couldn't find it there either. When the weather gets nicer I plan on going back up there to search again.
I did find a 1913 D wheatie, and 11 cents in clad....and about 3,457,384,295 nails.
On the plus side, it was fun, and he was grateful that I attempted it. With that 1913 wheatie there, there's bound to be more once I can focus on finding fun stuff, and now a lot of the nails are gone. I also now know where his pipes are buried
I do think I need a new detector though...I have an F2 and it had a hard time getting repeatable signals. I also brought a friend's Tesoro Silver uMax which I really liked, but the depth on that machine isn't very good. Only a couple of inches.