Anyone know about harmonicas?

My stepfather died in 2009 and left an expensive and hardly used harmonica, which has lain unused in its case ever since. It's a Hohner Amadeus, and apparently it cost him about £2000 in 2008, although you can find one on Amazon now for £980. My mother would like to sell it, as nobody in the family has any use for it.

The question is, does anyone know if it would be possible to sell it, how, and how much would it be worth? I'm trying a few avenues for this, and thought it was worth a go on here just in case.