Illusion, hallucination or delusion?

What you are describing is exactly the type of concerns my DW expressed daily earlier in her dementia journey (she is now in Stage 7e and on hospice.). When we got back from an outing she would search the house wondering where “everyone” was. When we would take our lone dog for a walk she would fret about where the “other” dog was. Where were her (long dead) parents? Occasionally when returning to our home she would refuse to go in, convinced it was not our house. And so on.

I consider these delusions, probably based on memories of earlier times like when our house or her childhood house was full of people. I wouldn’t worry to much about a label for this, but I definitely advise just making a written description of these behaviors to give to his neurologist just prior to any visit. Hopefully then your neurologist will know what the issues are and be sensitive enough not to have to extensively discuss this in front of your DH.

My husband with Alzheimer's does this exact same thing! Always asking where are the people, when are they coming, where is that woman, etc. Sometimes he sits on the front porch just waiting for them to come. He also asks many evenings where do we sleep. I usually just say I don't know where the people are or no one let me know, but we can let them in when they arrive. Luckily he doesn't get too distraught or worried so I usually just move on or distract.

@mathreader

This was my sister (Peggy) starting about a third of the way through stage 6 to the beginnings of stage 7. In her case it was The Lady, who was always trying to hurt one of us. I never did figure out who The Lady was. And the way my sister referred to her, you could hear the capital letters in The Lady. Needless to say, there was no one there.

Occasionally Peggy would forget where her room in memory care was, or even that she had a room. One time she told me she was going to have to sleep on the couch because she didn't have a room.

Then there were the times when she'd see birds fluttering around in the trees outside her bedroom window (in memory care), and swear that they were cats. We'd just remark that the "cats" were cute. Usually I'd just roll with whatever was happening.

When The Lady hallucination got to be too much, we'd increase Peggy's medications.

I'd consider what your DH is going through more as delusions, than hallucinations (unless he's seeing the dog or the little girl.)

it is a lonely life. Like you, I often don’t start conversations. I always think before I say something, I miss having a partner to talk to about anything. We do still laugh though, so I’m very lucky there. I dread the day he stops laughing.

Before my DH’s doctor’s appointment, I wrote down things I wanted the Dr to be aware of and then handed the folded paper to the nurse while my DH was on the scale. She gave it to the doctor prior to him coming in the exam room, so we didn’t need to discuss anything in front of my husband.
I wrote:

Daily hallucinations: sees people and animals that aren’t there.

Daily delusions: makes up stories in great detail that aren’t true.

Occasionally wakes up at night very agitated and takes the bedding off the bed and remakes it over and over. He says he’s too hot, no too cold.

Mood swings with many angry episodes, calls me names and orders me to get out.

His doctor prescribed Seroquel at that visit. Although the hallucinations and delusions are still happening, there is no agitation or anxiety during the episodes.
Example: The other night he asked me very calmly if he was in trouble. I asked if he meant in trouble with me? He said … no, just in trouble. I said … no you’re not in any trouble. He said … I wondered because that man has been standing there looking at me for about 15 minutes. I said, “Oh, no you’re fine; not in trouble.” And that was that … no fear, or anxiety … just a conversation. It was very different before he took Seroquel.

@mathreader and @trottingalong I hear you about not starting conversations. Nothing about dementia lends itself to a brief response. Even now that Peggy has passed away and people ask something about her, I just answer briefly and move on.

And you know what @trottingalong , your DH may still have a lot of laughter in him. Peggy and I used to laugh and joke about stuff all the way through stage 6. Not so much after she hit stage 7, but even then I could sometimes get a smile out of her, or even a "you're so funny" in response to some good-natured snark.