Harris presents small business plans; Trump admits losing 2020 race

William has the KCNQ2 genetic variant and suffers from epileptic seizures.

Fred Trump, 61, said he believed the former president and other family members had left him out of his grandfather's will years ago, and later said the former president and his aunt had agreed to set up a fund to help with William's care. He said the money “never really materialized,” and last year, when he called the former president to ask for financial help with William's therapy, his uncle made the comment.

“I said, ‘No, he recognizes me,’” said Fred Trump, who recently published a book about his experience growing up in the Trump family. His sister, Mary Trump, has already published a similar book and has long been critical of their uncle.

Reached for comment, Trump campaign communications director Steven Cheung said the story about the former president's nephew was “completely fabricated and fake news of the highest order.”

“It’s appalling that such a disgusting lie could be printed in the media,” Cheung said. “Anyone who knows President Trump knows he would never use such language, and false stories like this have been thoroughly debunked. This is nothing more than a small campaign to sell copies of a book that should be in the bargain bin of the fiction section.”“

The former president's nephew said he believes in Vice President Kamala Harris' policies and would be willing to campaign for her, including in key states where he has ties.

“If asked, I will campaign for the Harris campaign and get the message out. My mother was born in Kalamazoo, Michigan. I would love to go to Michigan,” he said. “I went to Lehigh University, as did my father and my son, Christopher. Andrew went to school in Philadelphia. I have family in Pennsylvania, which is a very important state, and I say I’m a different kind of Trump. I think I can fit in with any group of people.”

NBC News has also reached out to the Harris campaign for comment.