How to manage dad, he's got alzheimer's. Got appt for dialysis assessment. He's agitated, angry, often combative?

Psychiatric eval. Please have him see a geriatric psychiatrist who are trained to help with these symptoms.
A big challange! If dialysis is to be permanent you really need to think very hard about starting it. As you know this is a choice that only he could make but now you will need to decide for him. No matter what type of dialyisi it would require his cooperation and sedatives alone can only work temporarely. The main question to answer is how much quality of life he would gain by going on it.