What is agitating him? Is it when they wake him up, get him ready for a bath, or is it just random? Before we find a solution we have to figure out what is agitating him. It may be a certain nurse or two, or perhaps it’s something they are saying, or even the way that they are approaching him that he doesn’t like. If it’s random when he gets agitated, talk to a physician about the medication he’s on. It could be that he’s on something that’s causing some of that agitation, OR he could potentially get on something that could help. A doctor will be able to help you on the medication side of things.
With regards to the redirection: embrace his reality. Even though it’s a sad reality that he’s living in (his wife and kids were killed) you could try and ask him about that. Get him to tell you about it and how much it hurts. Look at old photographs with him. Talk about things he loved about “his wife and kids that were killed.” He’s probably confused because your mom has passed away, and now he’s feeling so sad over that loss that he’s expanding it to the rest of his family. Chances are, there will be days where he doesn’t think that “reality” is true. He’ll probably have days where his wife AND his kids are still alive and well. I know it’s a sad reality that he’s created, but it will be even more confusing if you say, “But dad, we’re still alive!”