Hospital visit causing dementia/child-like behavior in my dad

Hello, I was hoping to get some advice/just see if anyone has experienced anything like this before. So I saw my dad (82) on Christmas everything was fine, he was his usual self, etc. He doesn’t have any serious physical problems besides being overweight and a bit unsteady on his feet (but can still get around independently, do chores, etc). He is also a heavy drinker but nothing too concerning. A few days into the new year he broke his foot in his house and called the ambulance who took him to a hospital about an hour away (two hours from my home). They had to do surgery on his foot, put it in a cast, and moved him to a rehabilitation facility a few days later.

Since the surgery/when he was placed in the rehab he has been completely unbearable. It’s hard to describe but he is just agitated, calls me screaming and crying multiple times a day, says I have to come ‘help him,’ claims the nurses are ‘cruel,’ and is just overall reverting to a state that seems sort of child-like? I know this sounds awful (and it upsets me as well) but I have been to the rehab, my husband, my brother, and I have been visiting often, and no one seems ‘cruel’ at all. I’ve met with the nurses, aids, social worker, psychiatrist and they have been very nice and helpful.

I arrived there to visit once and they had him in a wheelchair and he was SCREAMING and CRYING telling them to move him back to bed. I said why don’t we go down to the coffee shop just to change scenery/do something? And he continued to scream at the top of his lungs and cry that he wanted to get back into bed so I said fine. Two of the aids held under each of his arms and said to put his weight on his good foot too help lift him out of the wheelchair and get into bed, he refused to do it was screaming /crying it was a horror show. He has also been having accidents in his bed and he has never done that before.

Basically I was wondering if anyone has experienced this before with their own parent(s)? He was fine just a few weeks ago on Christmas and since this hospital/rehab visit for a broken foot he has COMPLETELY changed. It’s almost like he has reverted into the mind of a child and it’s very difficult to hear/deal with. I’m not sure what to do or if there is any way to help.