Tyler Dooley has spoken publicly about the nuptials between his aunt and Harry, saying he wants to “set the record straight”.
The 25-year-old medicinal-use cannabis farmer appeared on a reality TV show discussing his family. He is the latest member of Meghan’s family to publicly offer his opinion on the marriage after Meghan’s sister, Samantha Markle.
Mr Dooley hit out at the royal family, claiming they could have offered more guidance to the Markles.
He also said he was disappointed to have not been invited to the May ceremony, which was watched by millions.
He also defended Meghan’s father, his grandfather, Thomas Markle, and said: “He worked hard for my whole family, for my whole life.”
Mr Dooley said Prince Harry was "a pretty cool guy" and he was happy Meghan had found "someone that she loves".
Appearing on MTV's the Royal World, Mr Dooley described himself as a "farm boy" who grew up seeing Meghan "as a sister".
In conversation with another cast member it was also revealed that Prince Harry used the pseudonym "Gary" in the past when meeting strangers.
Mr Dooley's father is Meghan's brother, but because they are no longer on speaking terms he uses his mother's surname Dooley.
When Meghan started dating Harry it began what Mr Dooley described as a "really tough journey" for his family.
"My family has been torn apart," he admitted.
"Had we some guidance and assistance, perhaps from the royal family, we could have avoided a lot of this stuff."
Meghan's extended family have hit the headlines on numerous occasions for public comments about her wedding and relationship with them.
The duchess was walked down the aisle by Prince Charles after her own father was unable to attend.
"Obviously (he) should have been there to walk his daughter down the aisle but he's her father," Mr Dooley said.
"He loves her more than anything in the world."
Mr Dooley revealed his whole family thought they would be invited to the wedding, only for Meghan's mother Doria Ragland to be the sole representative.
"Your family that was raised with you, you can't forget them," he said.
"It doesn't matter if it's a royal wedding or whatever but I'm just happy that she found someone that she loves."
During the second episode of Royal World, cast member Jessica Heydel described an encounter with Prince Harry.
"He was introduced to me as something like Gary or something like that," she said.
"I sat down there and I thought, he doesn't want me to know who he is but obviously I know who he is.
"He was asking me all these questions and I literally could not say a word."
In May it was reported Mr Dooley had allegedly tried to enter a nightclub carrying a knife, while visiting London at the time of the royal wedding.
He said that "vicious headlines" about him had been "hard" to take and he had been pushed to "breaking point".
Mr Dooley said Meghan had come from "humble beginnings" but praised her for being a good role model, especially for women.
"We used to idolise her as kids," he said. "Her personality is unreal, the smile, she's phenomenal."
The Royal World airs every Wednesday at 10pm on MTV.