Restoration of leather couch
There are leather softeners & waxes.
Clean it, condition it, and if needed restore the color if faded with analine dye. When doing clients couches annually I use these products and get great results.... https://www.youtube.com/watch?v=pt_o_qSgS3k&t=369s they have lots of videos on solving various problems
This might help: https://www.youtube.com/watch?v=ACB5WfieTRg
This may help: https://www.hometalk.com/39740914/redo-that-old-leather-couch