Good Morning Elmo!
*sigh* well... here is what my experience has been with this sort of thing. When the leather is cured and finished, there is a type of coating that they apply to it to give it that smooth finish. With time this finish wears off, it can be your steering wheel, seats, even things like a belt, shoes, pocketbook ot jacket.
One of the places I would start for reliable ideas on this project would be a reputable boot repair shop or saddle shop. They may have something that will refinish the leather. Another source is Tandy Leather.
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I have not used any of this sort of product they do have some things available via the internet. I'm just not sure what you can do with it once it has become rough. Maybe someone else in the group is a leather expert or has gone through this sort of thing.
Do let us know what you try, and if it works though!