There is a leather product called Cellugel, that is used in conservation.
it is a Consolidator, it penetrates the substrate of rotted leather and stops the deterioration but it does nothing to reverse it.

http://www.archivalsuppliers.com/pro...umber=993-0116

You could try it, but the leather would be no stronger or safer, it just wouldn't keep flaking off on your backside.