How do I help my father-in-law?

Thank you very much to all who have responded. You have given us much to consider and we are pursuing information on the local Alzheimer's association as well as many of the other tips you have mentioned. Again, thank you RallyPoint community for your advice, experience, and encouragement.

My father-in-law has Alzheimer's. He served in the Navy during the Vietnam era, and has VA medical care. He is also a violent person, and though he used to keep the violence in check, as he has degenerated mentally, he keeps it less and less in check. He's still together enough to fake out the VA doctors in phone interviews (thanks, COVID) and he will not give permission for anyone else to be involved in his care. The only way we know he was diagnosed is because he showed his paperwork to my kids when they moved into a place two houses down from us so we could be of more assistance. Anyhow, simply reminding him to take his medication or denying him permission to drive the car is enough to send him into a violent outrage. His wife and my wife are now both terrified of him. He isn't getting the care he needs. We've tried to contact the VA, but have run into a block wall of bureaucracy. I had help navigating it to get some care, a couple years ago after 5 years of sucking it up, and now I need help again to cut through the layers of government and regulations to get this man the help he needs and deserves.