Dealer Gone, Leather Needs Repair/Replacement

[cuse69]

This may be an old problem but I agreed to dear friend to help. Background: Austin sofa, chair and 2 ottomans in Cavalier Oxblood purchased 12/04 at Mastercraft, (a now defunct H&M dealer in the Washington D.C. area). Owners are pretty careful with their home and possessions and as my mom used to say "it's the kid of place where you could eat off the floors". Needless to say the sofa and one ottoman has been the most popular seating for the family of 2 seniors (that would be my age so no cute comments). After almost 11 years the sofa leather is breaking down severely on the seats and ottoman but has a nice attractive patina developed on the back cushions and arms. Obviously the cushions need either repair or replacement and the back cushion cores are needing some love. The chair and other ottoman are in excellent condition given their age. So here is the challenge, how to bring this otherwise good condition sofa and ottoman back to the quality and appearance that H&M furniture should have when the dealer is long since gone away? What is the best approach? Repair by refinishing or new leather cushion covers? (Photos 2,3,4) What about the ottoman? (Photos 1,4). Should this be left as is to deteriorate further or be repaired and if so how? I offer this thread since my dear friend knows I have been involved for many years on this forum and am a staunch H&M supporter. Maybe others face the same challenges. I have attached some photos to follow. I can answer questions if more information is needed and more photos are available if needed.