How do I tell my father that I’m going to put him in a dementia unit at the VA?

Dwiseman, now is the time to use "therapeutic fibs". Make up something that you feel your Dad would understand.

I see your Dad is living with you. Tell him insects were found in the insulation so there will be a lot of work to correct this, and you and him need to move out for a short time. Tell him you have a friend you will be staying with, and you found him a nice place at the VA, where he can be around other military guys.... look at all the stories they can exchange with each other :)

Who knows, he might like being there.

We told my Mom she was going to a new apt where she would meet new friends.