Chris Salvatore, 31, met Cook when he moved into her Los Angeles apartment building five years ago.
"Today" reported in January that Cook, who had leukemia, was in the hospital with breathing issues and pneumonia. Doctors said she could not return home without 24-hour care, but that care was not covered by Cook's insurance.
So Salvatore created a GoFundMe page to raise funds for his friend and neighbor, to whom he referred as his "friendly but sassy" grandmother. The page raised more than $77,000, surpassing its $60,000 goal.
But round-the-clock care proved costly, and the funds quickly dwindled, according to "Today," so Salvatore invited Cook to move into his apartment across the hall.
"She couldn't be happier that I asked. I was over there visiting most days anyway," Salvatore told Today in January. "The only other option was for her to go into a facility. I just couldn't do that to someone who is like my own grandmother."
"It's with a heavy heart that I share the news that earlier this morning the world lost a truly inspiring, beautiful woman. Norma is now resting peacefully in the eternal, and while she may no longer physically be with us, her spirit will continue to fill the hearts of so many people. Perhaps Norma's lasting legacy is that her story helped the world to see the true meaning of love. Norma reminded me that we all are created to love and all desire to be loved."
Salvatore told "Today"what he learned from Cook.
"She taught me to love so much deeper than I ever could imagine possible," he said. "She opened the hearts of so many people during a time when it was desperately needed. She was a truly powerful woman who had the ability to bring people together who may not have crossed paths otherwise."