Now that flatout sucks tiger. what an a**hole. if it is that rare i would be going to your local antique shops and showing them a photo tell the story give them your number, keep an eye on gumtr and fleabay and the like. thats a low act. i feel for ya man. hope ya have another type of rare mower to restore mate. I put my good ones in the roof.
Condolences on your loss.
Sean