Kathleen Rogers, a friend and former publicist, told The Associated Press that she was so concerned she contacted the Maine Department of Health and Human Services to investigate six to eight weeks ago.
Through tears, she said did not want Indiana to be remembered for shutting out friends and closing his studio.
"He was a better guy than he's been portrayed as being. He was reclusive, cantankerous and sometimes difficult. But he was a very loyal, loving man. He was the architect of love," she said.
A DHHS spokeswoman did not immediately return a message seeking comment.
As the story goes, Indiana, who was born in Indiana, settled in Maine after becoming disillusioned with the art scene in New York.
But he told The Associated Press in 2009 that he moved to his house — which a benefactor bought for him — when he needed a place to go after his lease ran out on his five-story studio and gallery in the Bowery section of New York City.
His desire for solitude was legendary.
He once stood up President Barack Obama at the White House. Another time he made a crew from NBC's "Today" show wait days before he would let them interview him. In 2014, he disappointed dozens of fans by failing to make an appearance outside his home for an event dubbed International HOPE Day, which was inspired by his creativity. Events were held in several locations around the world.
Although he created a wealth of art, the iconic "LOVE" tended to overshadow his other work.
Decades later, Indiana's other art took center stage in a 2013 exhibit, "Robert Indiana: Beyond Love," at the Whitney Museum of American Art in New York City. "Well, that's taken a while," he quipped.
In Maine, Mills said he was inspired by the Whitney's efforts to produce a 2016 exhibition, "Robert Indiana: Now and Then." It was one of the last major shows focusing on Indiana's work, Mills said.