Mistreated patients

Hi everyone! I was hoping to get some advice on how to deal with health care workers mistreating patients. Yesterday me and my coworker dropped off an old lady back to her retirement home. She was quite old and didn’t really know what was going on, she was able to answer some questions but was mumbling nonsense the whole time. I believe she was a case of dementia. I am used to dealing with patients like her and never had any issues, we treat everyone respectfully no matter what. Unfortunately her retirement home isn’t the nicest, but I have never seen such treatment from a healthcare worker (not sure if they were PSW or nurses). When we arrived not even a word was exchanged between the workers and the patient, they immediately started moving her to a bed like she was an animal (I wouldn’t even treat an animal like that) and started stripping her down, she obviously got agitated and tried to tell them to go away but they completely ignored her. My coworker and I could not believe what we were seeing. We were with this lady for at least 30 minutes before we arrived and she was extremely nice (even tho she was out of it). The aggression from the workers obviously agitated her and that is an image I will never forget. Unfortunately we were in shock we didn’t even have time to say anything, we went back to the ambulance and had to sit in silence for a moment. She is someone’s mom, she is a human being, she does not deserve such treatment. I have not stopped thinking about all the things I could’ve said, unfortunately I froze. I don’t want to think about all the old folks living in that place and being treated the same way. I go to that home frequently and I will definitely say something next time, how would you approach a situation like this? I don’t want to come off aggressive or sound like I am telling them how to do their job, but something has to be done.

[UPDATE]: Thank you everyone for your advice! I just got off the phone with my manager and the place will be reported. I hope this gets to the right hands and the place is investigated.