Scott,
That's pretty curious. I have a partnership in a Super Viking that was covered with Ceconite in 1972 and it has some cracking but nothing along what I see in your pics. Some of that looks like significant delamination which I kind of doubt is due to not being hangared. Looks like it is more on the underside of the wing too which I think would rule out UV to a degree. Can you see a layer of silver underneath the top color? How about a layer of blue or green under the silver? If they didn't seal the fabric with nitrate dope first, the butyrate wouldn't adhere and you could see some unusual peeling. They could have also put on a polyurethane top coat which is not advisable and known to crack but likely the fabric underneath is in fine shape.
https://www.eaa.org/eaa/aircraft-buildi ... ite-fabric?
Where has the plane been kept since 93? If someone didn't follow the process correctly, they could have applied the Butyrate directly to the fabric which would be a no-no for the system.
If the plane is otherwise in good condition, I would factor it into the sale price. It can certainly be fixed.