Hi Luke,  Here are a couple facts that you might find interesting.
Cast iron will bring about $0.06 per pound.  If the harp in your piano
weighs 100 pounds, you'll get six bucks.

If it's an old piano, it probably has ebony keys.  On eBay, you could
probably get a reasonable amount from crafts people because ebony is
rather scarce today.  Same goes for ivory from the keys.  A set of
88 keys sold on e-Bay recently for $40.  But don't try it in New York
[a New York state license is required].

There is a lifetime supply of piano wire of various sizes, too, and you
can salvage about 100 pounds of various types of wood from the case.
There are several large posts in the back, a big piece of hard maple
in the pin block, lots of veneer and poplar in various parts if you can
find a woodworker who will take it.  I made a nice woodworking bench out
of an old piano once.

If your brothers think the piano is valuable as is, let them put it on
Craigslist for $50 and see if it sells.

Regards,
Craig Smith