Prince Harry is set to receive a substantial inheritance of $8.5 million from his late great-grandmother, the Queen Mother's estate, upon his 40th birthday. However, royal experts suggest that this windfall is causing further strain within the royal family, particularly with his brother, Prince William.

According to reports, the Duke of Sussex's inheritance surpasses what Prince William received on his own 40th birthday, a situation that some insiders say has left the Prince of Wales feeling "disgruntled" amid ongoing tensions following Harry's public criticisms of the royal family.

"Prince William feels that Harry has been unsupportive, scathing, and hurtful towards the royal family," said Helena Chard, a British broadcaster and photographer, in an interview with Fox News Digital. "Harry, on the contrary, will be elated that he has won the top prize as he has always felt inadequate to Prince William."

The Queen Mother, who passed away in 2002 at the age of 101, reportedly placed two-thirds of her estimated $120 million fortune into a trust fund for her great-grandchildren. Christopher Andersen, author of "The King," explained that the value of the trust has increased over time, boosting Harry's share along with it.

"She knew that when Prince William became Prince of Wales, which he did when his father became king, he would inherit the Duchy of Cornwall, which now boasts assets of over $1 billion," Mr. Andersen told Fox News Digital. "In the meantime, the value of the trust has simply increased, Harry's share along with it."

Royal expert Hilary Fordwich suggested that Prince William is not pleased with Harry's forthcoming inheritance. "Purportedly, Prince William isn't happy that Prince Harry will be inheriting $8.5 million from his great-grandmother, the Queen Mother's estate," Ms. Fordwich told Fox News Digital. "It's not so much that he resents the money in any way. But the Queen Mother couldn't have anticipated what Prince Harry has done to the family."

Ms. Fordwich drew parallels between the current situation and the abdication crisis of 1936. "She loathed Wallis Simpson for the damage she did to the monarchy and their entire family," she said, referring to the American divorcée whose relationship with King Edward VIII led to his abdication.

Some experts believe that King Charles III might feel relieved that his younger son will be financially secure. "King Charles will be mighty relieved that Prince Harry will now be financially comfortable for a while and not feel the need to write further memoirs attacking the royal family," Ms. Chard asserted.

Despite the inheritance and potential financial security it brings, tensions between the brothers appear to remain high. Royal expert Michael Cole told GB News that while the Prince and Princess of Wales acknowledged Harry's birthday on social media, it does not signify a reconciliation. "I would say it is definitely not an olive branch," Mr. Cole said. "They are still at war."

Ian Pelham Turner, another royal expert, believes that the king should initiate peace talks with Harry. "In my personal opinion, this milestone should force King Charles into action rather than inertia and become the monarch Britain expects," Mr. Turner told Fox News Digital. "The inheritance is a sad reminder that his great-grandmother saw the best in him."

As Prince Harry turns 40 and becomes $8.5 million richer, the question remains whether this financial boost will ease tensions or further complicate relations within the royal family. For now, the rift appears unresolved, with experts suggesting that the path to reconciliation remains uncertain.