This is wild.

"That is wrong that is wrong blah blah blah." Wrong on who standards? Yours? What is right and what is wrong is culturally relevant. (including religion) Is there a universal moral law? Let the owner deal with his grief by making his cat an art piece for everyone to remember and be amazed (or freaked) If that calms his suffering let him be and stop prescribing what is right to him or to anyone else.