Hi Chris. Are you a member of the APS? If so member prices for a certificate range from a minimum of $20 per item to a maximum of $400 per item, depending on value of the item. If it is determined to be a fake you still have to pay the minimum. If you are not a member of the APS, these fees are doubled. It can be a costly way to confirm a fake when it is already obvious that it is.
Regarding your thinking about planning ahead for a family member who will
inherit your collection - that is a very good idea, but you should consider whether that family member is as committed to collecting as you are. Typically that is not the case and heirs often just sell the collection. If that is the case then you should discuss with that person how to sell your collection and get more than a few pennies on the dollar for it which is what many dealers will offer in such a case. You will need to be very realistic as to the actual cash value a dealer will really pay and not what might be obtained if sold off one cover at a time through auctions as most heirs would have no patience for that. Give your future heir the telephone numbers and other contact information of a couple of an auction houses or dealers who would actually be willing to buy or consign your collection. Unless your collection is full of high value rarities of the kind that are featured on the front covers of auction catalogs or in dealer's ads of what they have for sale finding such an auction house or dealer for less spectacular material may be difficult.