My heart goes out to you! I am a geriatric care manager and RN. most people with dementia become highly irritable and have an increase in their confusion, sometimes to the point of hallucinations, when there is acute pain or infection. Your dad isn't himself right now, and you'll need to wait for his conditions to clear, to find out how much improvement, if any, he will exhibit. The health team is trying to use medication to turn his cycle around. It may be time to call for a care conference and bring up all your worries. You may want to hire a geriatric care manager to be present at this meeting. It helps to have a third party listen in, advocate for you and your dad, and be a voice of reason for everyone. It may be a couple months or more before he is stabilizing. Good luck to you and your father!