John Mulaney has a good piece on how he bought a Rolex brand new from an AD then walked across the road and sold it at an eye watering loss to a dealer just so he could get cash for his gargantuan cocaine habit. That's probably the best investment you'll get out of most watch purchases.
SuicidalGuidedog
That is quite bizarre. Monochrome described it (below) but that doesn't really explain the thinking.
THE PRINCELY TOUCH As with all “Le Petit Prince” editions, the dial features the signature deep blue with a sunray-brushed finishing. The vertical layout of the counters is clean and symmetric with a recessed and snailed 60-minute totaliser for the chronograph at 12 and small seconds at 6 o’clock. The large stylised Arabic numerals are applied to the dial and filled with luminescence, as are the propeller-style hands and the triangle and two dots at noon. Substituting the numeral 3 is a date window with a white background.
It would be the same way it can track the phases of the moon. Assuming the watch knows where it is in the world (either by GPS or on older ones by you setting the location), the rest would just be a reference to tide charts. They change daily but so do moon phases. In fact, the two things are connected (moon and tide).
Chrono24. But I'd pump the brakes on checking the price and mentally banking that cash. If your grandfather was wealthy enough to ignore a valuable watch then great, you might be in luck. But if he was not particularly well-off it seems unlikely that he'd leave an extremely expensive piece just bumping around randomly. Was it specifically listed in his will? If it's real, it probably should have been.
I'd look at it another way. Audemars Piguet Royal Oaks have never been cheap. They were always luxury from the day they were created (unlike, for example, some Rolex). So this would have always been an expensive and exclusive gift. I only say that because you mentioned in another comment that it was gifted to your grandfather. There's a (remote) chance he didn't know the value and left it banging around, but there's zero chance the gift-giver didn't know the price. So the question is: did Grandpapa know anyone who could give gifts like that and did he do anything worthy of that kind of gift? I'm not talking "he was top used car salesman for July in Ford Pensacola", I'm talking "he signed the deal that brought the Rams back to LA".
If the answer is "I don't know" then I'd assume it's fake until you get the authorized document from AP (which will cost you a few hundred bucks by the way).
I think you already have the info on this: take it to an Authorized Dealer (or an actual AP store if you're close to one) and get it authenticated. In the meantime, screw in that crown; it's giving me anxiety even if it's fake.
For you, the first half of their slogan is very true. "You never actually own a Patek Philippe..."
If you mean Automatic (Mechanical watches are generally split into Hand-Wound and Automatic) then yes. This is a JLC Reverso Squadra Hometime. There are other versions too though.
You might mean quartz (battery powered) but that's also true, there are some options in Reversos for that too. The classic, traditional one is the handwound one though.
Congratulations on surviving the stroke (and the other close calls).
As others have said: something to monitor your unreliable blood pumper is probably a smart move, but there's no reason you can't have both: treat yourself. Assuming you can afford it, watches are a good way to commemorate life events. Some events are bigger than others. The last nice piece I bought was to commemorate having enough money to buy a nice watch.