Upload & Sell: Off
Though I'm a lawyer in my day job (with a minor in ethics) please note that this does NOT constitute legal advice.
I would highly suggest that you find the estate of the deceased photographer, and contact them to request permission to use the photographs that the photographer worked so hard to create ex nihilo. After all, when your in-laws paid the photographer to take their photos, they weren't simply commissioning the guy's service of capturing their likeness in a 2-D projection on some physical medium. Oh no. What they were actually doing was DONATING money for the PRIVILEGE of working as the photographer's models so that the photographer can create and own the photos and control everything that happens to the photos henceforth.
After all, it takes an UNIMAGINABLE amount of creativity, hardwork, and sacrifice (perhaps even the ultimate sacrifice) to tell some people to pose a certain way, set up some lights, and push the shutter release. If you now simply make a duplicate of these photos (which your in-laws already paid for, and which have no value to ANYONE ELSE BUT THE FAMILY), you are disrespecting the photographer who OWNS those photos. Even if the law says the copyright has elapsed, it would be UNETHICAL to copy those photos.
In fact, I take back what I said previously about requesting permission from the photographer's estate. You should simply contact the estate, inform them of your appreciation of the artistic genious that went into those photographs, and then donate those photos back to the proper ownership of the estate.
After all, that's how it works in all other professions. In Hollywood, the camera operators own the footage to the movies they shoot. Any editing, production, or release must first obtain the blessing of the camera operator. In contracting (for example our recently remodeled bathroom), the contractor owns the actual bathroom. We don't actually get the use the bathroom (even though we paid the contractor to do the work), since the contractor owns it. But each morning we walk by the bathroom door, admire the beautiful work, and go outside to to do our business in a hole in the front yard.
This is the standard in all other industries, so why is it some people think they own the photos that they paid the photographer to take? An outrage.
In my business model, I actually charge clients by "the look". What I mean is they incur a fee each time they LOOK at my image. Brides love this concept, since they actually save money in the long run. However, I've found that some people are sneaking around my ownership of their wedding photos by not actually looking at the photo, but by simply THINKING about it. As anyone with any knowledge of brain physiology knows, just thinking about something actually generates a low resolution residual image in the visual cortex. That sounds like COPYRIGHT INFRINGEMENT to me. I'm now currently working on a way of being able to detect, and thereby charge for, the thinking of any of my images. I'm pretty close.
Can you imagine a world where people actually OWN the things they pay for? That would be utter anarchy. Owning a home? Outrage! Everyone knows that real estate and homes should properly belong to the bankers; people shouldonly be allowed to rent. We're not quite there yet, but we'll get there soon (and get rid of these evil concepts of "free" and "sharing").