Fading memory for dress codes

We were at a family lunch today with my old mother who is in her 90's and whose memory is disappearing at a progressively faster and faster rate. She used to be such a stickler for doing things properly such as laying the table, correct table manners and correct dress code for every different type of occasion from a formal wedding downwards. She now can't remember. Mind you the world has changed and nobody does things as they were done 90 years ago.