How do I calm Mom when she insists she has to get to "the kids" when there are none?

My Mom was in an AL that was one floor and sort of a square/rectangle shape. She was able to walk the hall that ran aound the whole inside of the building. I went to visit one day and she was all in a tizzy walking the hallway. I asked her what she was doing and she said trying to find the baby that was crying. I told her there were no babies in the building only adults. She looked at the Medtech who was standing there and said "I don't believe her (me) but if you tell me there are no babies, I will believe you" The Medtech told her there were no babies, Mom said OK, and walked away.

Its so hard to say the right thing that won't upset them. Sometimes you just have to go along with them. Maybe just say "Mom you know the kids have made other plans for dinner tonight. Thats why you are having dinner here" Then pray that she forgets what you said so u can use it again.

Tell her that:
"Betty, Susan and Brian" called and said they are having lunch (or dinner) at Cathy's house then they are going to go to a movie. (or study) and they will be home later.
or
The kids went shopping for a few things when they get back they want to surprise you and make dinner.
or
The kids are at school right now, we have plenty of time to get dinner ready. Why don't we go for a walk now.

Anything that you can say to help change the subject, deflect the situation is fine.

I used all of SJP's tips. They worked most of the time, but mom would remain worried. I was hard to get her out of those cycles.

Mom took Seroquel to help with the windowing issues and worry about those little girls was frequent. She started Seroquel with 12.5 my daily at 4:30 that gradually increased to 75 mg over the course of 3.5 years.

What would you say if there were kids to look after? Try to imagine that scenario and how you would respond. “The kids are staying overnite at their friends house (or they're staying at their friends house today). You don't have to cook today.” “ The family went out for dinner today”. “It's too early for lunch (dinner), we'll go in a couple of hours”. Once you respond, immediately offer a change of subject. “Let's have a snack”, “Let's see what's on TV”, “Let's go for a walk”, “How about a cup of coffee?”.

Have you watched any Teepa Snow videos on redirecting and comforting agitated dementia patients?

In the end, you may find that medication to take the edge off these delusions is a good way to go. A geriatric psychiatrist can help.