When I read the OP's request for an "old CD player" for an "old guy" I was motivated to do a Google search. Using the key words: "CD player", "very large buttons", "large, bright display", "oversized door (for "error correction" when sloppily placing CDs in the tray -- perhaps even have a feature that flips the CD over when placed in the draw upside down?", and response above 4k optional (we can't hear above that frequency), I was directed to the Fisher Price website.
But, seriously, I think the old Sonys were wonderful players, and for "newer old players" the Marantz CD80005 is one of my favorites.
But, I did get a chuckle to OPPO being referenced as an "old player". This would be like a first generation Tesla referred to as a "vintage automobile." Guess I'm showing my age here?