I worked with the elderly too and have seen mean elderly people - probably in some stage of dementia, but they've hurt other residents and nurses. But, I have also seen mean and abusive family members and staff hurting them.

In my last workplace, I was stalked by a female bully. No one believed me that she was doing it to me. She was finally caught hurting someone else and was fired. It's hard not being believed. It does something to your soul.

Thanks for your great response @trudeehunter!