Basically the answers to all your questions are "yes" and it sounds like you've come to that conclusion for yourself anyway based on your phrasing, although I'm not sure they claim to be investment vehicles.
Generally speaking, modern precious metals coins/commemoratives purchased from any government or private mint are going to have a large premium over spot and can easily be found on the secondary market (e.g., ebay) for closer to spot within a couple of years. Certainly they of interest to certain collectors, but the market is limited. They are indeed worth their weight in gold, but you need to take into account the fineness.
If you don't want to bother much with it, the fastest way to offload is going to be to take it to a coin dealer, but that probably won't get you the most money in your pocket as they have to make money.
At the end of the day, many of us aren't concerned witih return on investment when it comes to coins / numismatics and don't even consider them an investment at all. We do it for the enjoyment of it with the understanding that rarely does one profit off of a hobby. Hopefully your father was doing it for the enjoyment of it all and wasn't duped into a get-rich-quick scheme.





















