What can I do when my father has been displaying rage, confusion and aggression?

My mother-in-law did this as well. I used several different approaches with her but distracting and re-directing worked best.
When we were going for a doctor visit, I wrote a note in advance to the doctor and handed it to the nurse with our paperwork. On another occasion, I stepped out for a "drink of water" as the nurse was leaving us, and spoke briefly to her in the hall.
My heart goes out to you as rage is difficult to see and deal with. I learned a lot going through it with my mom-in-law. I wrote a book full of tips, idea's and suggestions, called "Caregiving: How To Hold On While Letting Go" and it's on Amazon. I think it will really help you!
Try to laugh as much as possible instead of crying. I pretended it was a video I was watching. It's easier to see the humor if you can take a step back.
God bless you on your journey!

You need to visit your fathers doctor without him and explain all the symptoms without your father being there. All the best.