Former Florida governor Jeb Bush, accompanied by his wife Columba, arrives at a town hall meeting at Loras College in Dubuque, Iowa, May 16, 2015. (REUTERS/Aaron P. Bernstein)

BEDFORD, N.H. -- Presumed Republican presidential candidate Jeb Bush revealed Wednesday night that his 94-year-old mother-in-law has dementia.

Bush said that Josefina Gallo Esquivel lives in her Miami home and is cared for by his wife, Columba, and his wife's sister, Lucila.

"She's a gift from God, she's the most beautiful woman I've ever met," he told reporters after a house party with voters here. "Just totally faith-oriented, just the sweetest, nicest person. And she suffers from dementia. It's not uncommon, this is a huge problem."

An estimated 5.3 million Americans of all ages have Alzheimer's disease, according to the Alzheimer's Association.

Earlier Wednesday, Bush raised the issue of Alzheimer's research during a meeting with voters in Portsmouth. Bush raised his hand as he asked people in the crowd to raise their hands if they have a relative with the disease.

Reporters asked him Wednesday night to clarify which of his relatives has the disease.

Over the course of his travels nationwide, Bush has said several times that he supports more federal funding for Alzheimer's disease research.

In March during a visit to Cedar Rapids, Iowa, he met a local teen beauty queen who told him that her community service project was focused on helping people with Alzheimer's.

"How many people here have a family member with Alzheimer's disease or dementia?" he asked the crowd in response. Nearly a third of the people in the room raised their hands.

"This impacts almost all families, so I appreciate it," he told the young woman.

Columba Bush remains an intensely private political spouse who rarely travels with her husband to political events, although she did appear with him last weekend in Iowa. Born in Mexico, Columba Bush has a difficult family history. A Washington Post story from March recounted that her parents had a stormy relationship that ended in divorce in 1963. She remained estranged from her father until he died in 2013.

Columba’s older sister Lucila married Jeb Bush’s friend John Schmitz. Both sisters eventually moved to Miami with their husbands, where their mother later joined them.