Sorry, but if your great-grandfather owned these, then he must have acquired them just a few years ago, because they're all modern mass-produced fakes.
There are a great many things wrong with most of the coins. While I share macmercury's unwillingness to allow the forum to become a university for forgery improvement, we nevertheless wish to see the forum become a university for
Counterfeit Detection. Therefore it might perhaps be useful to point out several faults with these coins, to give folks an idea of the kind of things that are wrong with them.
Coin 1: The shape of the numerals in the fineness mark, 900, are completely the wrong size and shape.
Compare with genuine.
Coin 2: This was never struck as an actual circulation coin. Extremely scarce patterns with this design exist but were never delivered to China.
Compare with genuine.
Coin 4: This "birds over junk" dollar has so much wrong with it that it really is "junk" in the common sense; sorry. As an example, a commonly seen error on these copies is "broken rays". Logically, the sunrays shining between and to the left of the sails should match up with a ray actually coming from the sun. Follow the red line and you'll see it doesn't line up properly on yours:

Compare it with this genuine example, taken from a coin sold at auction recently - it lines up perfectly:

Coin 5: Um, it's turning green. Silver coins don't normally do that.
Coin 7: See the comments made for both coin 1 and coin 5.
And some general advice for the newbies that might see such coins for sale either on
ebay or in the street markets: if you see even just one coin that's definitely fake, mixed in for sale with a whole bunch of similar coins you're not sure of, then you can safely assume that every single one of them is fake.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis