He has been scared of them or frightened until lately. He thinks they are drug dealers or people who mean to harm him. He says he can't see their faces. There is no one there....even my mom says so. How do you address this? I try to agree and say show them the door or leave the room and come back and they'll be gone.
My mom has no short-term memory and I've told her it's from her medications. So when she can't remember, I just say, "Well, you know it's just from the medicines you take." So there's no judgment there, just a matter-of-fact statement of what's going on.
Would anything like that work with your dad? "Oh dad, it's just your brain trying to confuse you. Mom and I are here to make sure you're safe and OK and if there's anyone in the house, we'll let you know." There's also a fascinating thread on this site about someone with Lewy Body Dementia and FTD Dementia. He's named his dementias and when his brain starts acting up, he's able to recognize that and it calms him down. If your dad has any level of logical cognition, maybe you can build on that with him.
The person I really worry about is your Mother. That is a lot of burden for her to deal with, especially if she is a senior citizen herself. Please note that over 30% of caregivers pass on leaving their loved one behind [as Pam had noted above]. Terrible odds. Watch out for your Mom, if she is becoming burnt out, something needs to be done immediately for her own health and well being.
There's a lot info out there about LBD. Jeanne Gibbs on Aging Care has walked the journey with her husband that had LBD. I hope she will chime in.
Hugs to you and your folks.