In a new interview with The Mail on Sunday, the 74-year-old retired TV lighting director alleges that he has no way of even contacting the Duchess of Sussex anymore, but he "won't be silenced."
"I'm really hurt that she's cut me off completely," he says. "I used to have a phone number and text number for her personal aides at the Palace, but after I said a few critical words about the royal family changing Meghan, they cut me off. Those numbers were disconnected, they no longer work. I have no way of contacting my daughter."
Thomas continues on, telling the outlet that he was hoping to send Meghan a card for her upcoming 37th birthday on Aug. 4, but fears she'll "never see it."
"If I send a birthday card to Kensington Palace, or wherever she's living now, it'll just be one among thousands," he says. "I thought about sending it by Priority Mail Express, but the Palace would probably just soak it in water for three days to make sure it doesn't explode."
The outlet also states that at one point during the interview, Thomas -- who reportedly suffered a heart attack just days before the royal wedding on May 19 -- feels it might "be easier" for his daughter if he died.
"It's lucky I'm still alive," he says of his health. "The men in my family rarely live over 80, so I'd be surprised if I had another 10 years. I could die tomorrow. It wouldn't be so bad. I have something of a Buddhist philosophy about death."
"Perhaps it would be easier for Meghan if I died," he adds. "Everybody would be filled with sympathy for her. But I hope we reconcile. I'd hate to die without speaking to Meghan again."
Thomas believes his daughter and her new husband, Prince Harry, will likely start planning a family within the next year, but fears he will never meet his grandchildren.
"What's sad is that some time in the next year, Meghan and Harry will have a baby and I'll be a grandfather, and if we're not speaking I won't see my grandchild," he notes. "How tragic is that, to deprive a child of its grandfather because I said a few things critical of the royal family?"
"They're just like a Monty Python sketch. Say a few critical words about the royal family and they put their fingers in their ears, cover their eyes and pull the blinds down. They don't want to know about it," he adds. "Meghan was apparently upset with me for saying that she and Harry will probably have a baby soon. But Meghan's been saying that herself for the past six or seven years, talking about how much she wants a family. Harry's been saying it too. That's fine. But the moment I say it, I'm persona non grata."
Thomas' latest interview comes nearly three weeks after he told TMZ that he just wants to be on speaking terms with the royal family.
"I was silent for a full year and the press beat me up every day saying I was a hermit hiding in Mexico, so I gave my story," he said at the time, seemingly responding to a source telling ET that Meghan and Harry were "frustrated" that he was continuing to do paid interviews. "Apparently that interview [with Good Morning Britain] put the royal family in their silence mode ... so, I gave another interview to break the silence. All they have to do is speak to me."
ET recently spoke with royal expert Katie Nicholl, who explained how the royal family plans to deal with Thomas' controversial comments.
"The strategy at Kensington Palace, I understand, is, 'Say nothing, don't dignify these comments, these interviews, these articles with a response,'" Nicholl said. "The royal family has had more than their fair share of scandals. This won't faze them."