But Prince William must not make promises about when Kate will be back at Adelaide Cottage, in Windsor, until he knows for certain.
Kensington Palace has said the Princess of Wales is likely to remain in hospital for up to two weeks after abdominal surgery last week.
The children are not thought to have visited their mother in the London Clinic and have continued going to Lambrook School in Berkshire each day.
Dr Catherine Wikholm, a child psychologist with the British Psychological Society and mother of two young boys, said: “Young children have the potential to be unsettled when a parent goes into hospital, especially if that parent is the primary caregiver.
“They are likely to be most scared about the idea of a parent not coming home, something going wrong during an operation, or even their parent dying. They may also worry something may happen to their other parent too.
“They are likely to ask questions about why their mummy is in hospital, what is wrong with them, what will be happening to them, and most importantly, when will they be back home?”
Dr Wikholm praised William’s decision to stop working in order to support his wife, look after the children and do the school run.
While George, 10, and Charlotte, eight, will have a greater understanding of the situation, little Louis, aged just five, will need more reassurance. “The parent should respond to questions calmly and honestly in an age-appropriate way – keeping details to a minimum, especially if some of the details are uncertain,” said Dr Wikholm.
“It can be a lot for a young child to process and it is important to not give too much information at once but let them know they can ask further questions.”
And she believes William is right not to have arranged a visit for them yet.
Instead it is thought the Cambridge children may have FaceTimed Kate and made her get well cards.
