BOSTON (AP) – Joan Kennedy, whose three children took temporary guardianship of her last year to ensure she receives treatment for her alcoholism, is putting her oceanfront Cape Cod home on the real estate market for $6.4 million – over her children’s objections.

“She’s not happy with the fact we have sought guardianship,” her son Edward M. Kennedy Jr. said Monday. “She’s basically trying to retaliate against her own children by taking one of the things we love the most, which is Cape Cod. It’s very sad.”

The attorney for the children, Augustus Wagner Jr., said that Joan Kennedy, 68, the former wife of U.S. Sen. Edward M. Kennedy, has no legal authority to sell the house on Squaw Island near the Kennedy compound in Hyannis Port. He went to Barnstable District Court last week to extend the guardianship order, so that any prospective buyer would know that the house cannot be sold.

The three children – Kara Kennedy Allen, 45, Edward M. Kennedy, Jr., 44, and Rhode Island Congressman Patrick Kennedy, 37 – took temporary legal guardianship of their mother last year.

Edward M. Kennedy Jr. said he and his brother and sister are “trying to save our mother’s life.”

“You can imagine how bad this situation has gotten for us to risk angering her and undertaking this legal action against our own mother,” he said.

“We tried to keep this private until the story broke a couple of weeks ago,” he added. “She tripped and fell because she was intoxicated. That is just exactly what we’re trying to stop.”

Joan Kennedy was hospitalized with a concussion and a broken shoulder after a passer-by found her lying on a Boston sidewalk on March 28.