You should try to use a cleaner and conditioner for leather. This one works on my leather bags and jackets. https://amzn.to/2ZnfhNX
Hope this Helps! Jeremy - https://do-daddy.com
Saddle soap to clean the leather and leather conditioner to keep the leather soft and supple.
I find a magic eraser to be great for getting out stains on leather and finish with a otter oil to recondition it
You don't say what's wrong with it if its drying out use saddle soap and a sponge it moistureizes the leather if its a tear crazy glue works well a tiny bit and put seam together then take a marker same color and touch up edges
What is it exactly about the leather that needs restoring? Is it dried out?
Is it worn down? Posting a photo would help illustrate the problem.