I'm sorry for jumping in so late to this thread.
I really send you and Dad (and family) prayers and empathy.
Even if our loved ones are lucid, hospitalization, surgery, meds, etc. can be so stressful. Hospital delirium is a real thing, only recently studied.
Hopefully once he's gotten some of the heavier meds out of his system, he won't be so distressed.
My husband went through some very challenging times with his mother the past couple of years. She's in a care facility now (in Covina). Sucks majorly that he can't see her due to Covid restrictions.