How to comfort a person with dementia in case of repetitive behaviours?

Let’s look at this example

Imran is taking care of his father Yusaf, because his mother, the main carer, is out of the house for a few hours. All seems fine, although Imran notices that his father is rather tense because Imran’s mother is not there.

Imran and Yusaf eat lunch together. Sometime after finishing lunch, Yusaf asks “When is lunch?” and, “What are we having for lunch?” Imran does not think much of it at first. Then, again, a few minutes later, Yusaf asks “When is lunch?”, “What are we having for lunch?”, and “Where is your mother?” Yusaf repeats these questions again and again.

Imran is confused about why Yusaf is doing this and gets more and more worried about his father. Imran continues to answer the questions, but gets a bit upset and raises his voice. Imran responds, loudly and is annoyed, “I have already answered these questions, why do you keep asking?”