Bennett, 94, gained his first pop success in the early 1950s and enjoyed a career revival in the 1990s and became popular with younger audiences in part because of an appearance on "MTV Unplugged".
He continued recording and touring constantly, and his 2014 collaboration with Lady Gaga, Tony Bennett & Lady Gaga: Cheek to Cheek, debuted at No. 1 on the Billboard charts.
Susan told the AARP that her husband had already begun recording a follow-up with Lady Gaga but that she was not sure he would be able to complete the task.
"We'll try," she recalled telling her son. "That's all I can tell you. We'll try."
He also performed a duet with Amy Winehouse, Body and Soul, which was reportedly the last recording she made before her death in 2011.
Bennett has won 19 Grammy Awards over his long career, including a Lifetime Achievement Award, and has sold over 50 million records.
According to the Alzheimer's Association, more than 5 million Americans are living with Alzheimer's dementia and one in 10 people age 65 and older has Alzheimer's dementia.
- Additional reporting, NZ Herald