Much much good advice in this thread, especially so from #9 and #13. My sentiments exactly.
I too have had the dubious honor (ha!!) of dealing with cameras from several deceased estates in the past.
Dealing with the family members was the most difficult task of all. Some believed every old camera in a collection was worth a mint. After listening to their arguments, I sent the disagreeing rels off to Ebay to check completed sales, which worked to an extent - as we know, Ebay prices are often all over the place, and auction returns on half-decent gear can be ridiculously high. So this tack didn't always work well for me.
If too many disagreements, I suggested we call in a highly reputable camera shop owner from Melbourne to evaluate the collection. Did this two times and it worked well. The estates paid A$250 plus travel costs. Faced with an expert (who started off by reassuring the family he was not interested in buying any of the cameras, so as to be completely impartial) the relations all came to the party quickly, and we were able to agree on final prices.
(Added later) I forgot to say this expert compiled a list and later emailed us written valuations of each and every item. Which made his fee well worth paying by the estate trustee and my tasks much easier afterwards.
The expert also resolved a personal problem I had with one estate, when I found a Rolleicord Vb kit I badly wanted. To my surprise, while evaluating this collection he decided the 'cord was too decrepit to be sold for the usual high prices, and put a very low value on it (I had no influence at all in this). With the family's agreement, I then listed the entire lot on Ebay and almost all of it eventually sold - most of the cameras i were 1960s to 1980s amateur models (notably a mind-boggling number of for-parts-only Instamatics!!) and took some time to clear, but in the medium to long term almost all went to new homes. It was all a bit like trying to dispose of unwanted litters of kittens and puppies, but it worked...
Anyway, to cut to the quick of my story, we put the Rolleicord on Ebay for the usual Rollei TLR high price. Nobody bit. At that time old Rolleis were not in great demand, and this one was (and still is) definitely a user model, if mechanically sound. After most of the sale was done the family had lost interest, so we pulled the few remaining Ebay ads and the family donated the remaining gear to local charity shops. They then kindly offered me the Rolleicord at a 'peppercorn' price and I took it. It's one of my favorite and most-used film cameras, so I did okay enough from the situation, although if I had put a dollar price on the time I spent cleaning and fixing up the collection before selling, writing Ebay ads (I let a family member who everybody trusted handle the sales and packing of all sold equipment), it would have added up to many hundreds of hours, endless meetings over coffee and cakes and occasionally stiff whiskies at the family's dining table, and having to negotiate every little point with demanding and argumentative rels, I would be a very rich man from the experience, and the estate would be much poorer. Which of course nobody wanted.
The two other estates I had to deal with weren't as difficult, but there were similar problems - usually to do with one family member in the group who was convinced that every old fungus-riddled thing in the dusty boxes in the back bedroom or the garage is worth a fortune. Leicas, old Contaxes, anything by Rollei (the 'cords currently sell for almost as high prices as the 'flexes, at least here in Australia) and the upper range 35mm and medium format gear, yes. Old consumer snapshot cameras from the '60s and '70s, no way, even if young shooters are now madly keen to buy a five pack of hideously expensive film so they can take the new camera out and show it off to the yuppie set.
My advice to anyone having to do all this, is to be sure to set the conditions of your involvement beforehand and stick to them, to the letter. Also consider bringing in expert help (my camera shop owner friend gave excellent impartial advice and saved me buckets of tears). Or find a reliable secondhand dealer and let them take the best of the lot on consignment. - Or use Ebay as an easy if expensive way to clear the stock.
One thing is guaranteed. After one such episode, you will vow to all the gods in the heavens to never, ever do it again. Until the next time...