I once had a wonderful, huge Burmese cat who lived to 24. It was amazing.
My mom had a Maine Coon for 20 years who came to her as an adult stray ... so she had to be well more than 20 y/o. Cat and mom moved in with us after dad passed and the cat adapted well to her new home. When mom passed, the cat mourned. I know she did; she was never herself again. Exactly one year after mom’s death, the cat died in her sleep under the chair where mom sat at the dining room table ... the spot where she’d get a tidbit off mom’s plate. ;)