Oh god nooooo, Dont force me to answer a question, LOL
Well, seeing as I'm a fully qualified Leather technician making leathers for just about ever car manufactuerer there is I'll shed some light on it. Most leather cleaners are a load of old tosh, conditioners etc, may add some moisture to the leather, and make it feel softer etc, but they do very little to protect or repair leather seats. Once they are going they are going, and thats it. Only way to repair is to put on what is on there in the first place, usually a mix of acrylic and polyurethane resins plus various waxes and fillers. This could be sprayed over the area in question, to hide any cracks etc, But after years of wear and fade it would have to specifically matched, and then you cant just do it with any old pigments, they need to be matched specifically to have no metamerism, This is a colours ability to change in various light sources etc.
various car refinishers use some dyes to hide the effects of scratches etc, But refinishing itself is complex as you need to use a solvent based resin, to cut through the original waterbased system applied to the leather, otherwise the finish will just fall off.
My suggestion is try and locate some new covers, even refinishing original ones, would mean that your applying finish to finish, and you'll end up with a plasticy finish with an awful break (piping and creasing in leather)
My suggestion for cleaning is nothing more than some luke warm, soapy water, and a gentle rub, dont waste money on expensive cleaners and moisturisers etc etc. Once a leather crust has lost its natural and articical fats, it will dry out, unless you retan the leather, moisturisors will not put this back in.
Repair dyes will just redye the crust leather, underneath the finished leather on top. Hides are allready pre dyed to match roughly the top colour, this means scratches are less apparent, if and when they occur. All you will do with a repair dye is darken this, shoe polish on black hides will do the same job if carefully applied into the scratch with a cotton bud etc, But repair dyes and anything else will never match the top pigment, so you'll still be able to see where its marked.
Anymore questions drop thee a pm.