This kind of thing is worryingly common in nursing homes and hospitals, sadly.
It's a job that desensitises people to suffering and if those in the job are just unskilled, low paid workers in it for the money, with no realistic ability to get anything better, then empathy goes out the window full stop.
With particularly violent cunts like this wanker, what starts as petty vindictiveness and self loathing eventually becomes physical abuse.
Hopefully he gets arrested and the victim gets proper, dignified treatment.