(((JD))) - I can understand how upsetting this must have been for you to see and listen to this man. It reminds me of that show "What Would You Do"? It was very good of you to try and get the owner to intervene but he didn't do a good job.
I wonder too about how bad he must be in private - if he 's that bad in public. This is elder/wife abuse. I think the card idea is good, but only if the abuser gets up to go to the washroom - so you can do it privately. She's most likely trapped and that's sad to think about. We need more people like you,

who are willing to stand up and notice when someone's doing wrong. It's a very sad situation.