Is there a free training video for staff at assisted living on how to deal with bullying?

There probably are films available, you would need to check with the owner of facility.

In the mean time, I came across this article https://www.agingcare.com/articles/nursing-home-bullying-174743.htm keep scrolling down the page even if you see advertisements, the article continues on.

There are some good videos on youtube by Teepa Snow about communicating, de-escalating and redirecting patients.