Dr Ed Owens, the author of After Elizabeth: Can the Monarchy Save Itself?, spoke exclusively to GB News to explain how the monarch should deal with the attacks from his son and daughter-in-law.
He said: “The most important thing here is how he is viewed by his own public.
Harry and Meghan have directed many attacks at Royal Family
“The King obviously wants to maintain a positive reputation with the British people.
“In that respect, the easiest solution is for him to try and maintain and keep hold of the moral high ground.
“So far, he's done that. He's done that by making it clear, sometimes through back channels.
“But often, it's through stories that go out to the press, from the palace, that he very much wants to keep the door open to Harry and Meghan, should they decide they want to return."
Prince Harry and Meghan Markle have released memoirs and documentaries about Royal Family
According to Owens, King Charles has put the "onus" on the Sussexes to end their bitter feud.
The commentator explained: “He is demonstrating that he is ready to reconcile and that ultimately, the onus is on them to make a decision as to whether they want to heal the wounds that have opened up between them and the rest of the Royal Family.
“The King has done that quite successfully so far. He's held the moral high ground, he's presented himself as a conciliator.
“That is the best way to maintain his reputation as a public figure."
King Charles should 'take the moral high ground', commentator claims
Owens compared the public opinion polls between King Charles and the duke and duchess.
"Let's look at the public opinion polls. We can see that both Harry and Meghan's popularity has slumped," the royal author noted.
"Even among young people who, among whom, they were extremely popular before their departure from the UK, and the King's opinion poll ratings have increased.
“So in relation to this subject, he's doing the right thing presently.
Meghan Markle and Prince Harry's popularity has slumped
“Whether there's anything more he can do, his hands are somewhat tied, because beyond trying to make specific concessions to Harry and Meghan, of course, they have requested an apology from the Royal Family for the way that they were treated.
“That would be essentially to concede that the Royal Family had done something seriously wrong in the first place.
“I don't think the King or other members of the Royal Family do accept the blame rests wholly with them, that the blame rests partly with Harry and Meghan as well. So I don't think that's an option presently.”