Liberal Senator Joyce Fairbairn won't return to the upper chamber "in the foreseeable future" because of health problems.
"She will not be in Ottawa for the September session," said Marc Roy, a spokesman for Liberal Senate Leader James Cowan. "Next steps will be determined based upon an evaluation of her health."
Mr. Roy declined to comment on the specific nature of the senator's health problems.
But Conservative Senator David Tkachuk, who chairs the Senate committee on the internal economy, said he received a letter last week explaining that the senator was living with Alzheimer's and had been found to be mentally incompetent. The letter was written by the senator's niece, Patricia McCullagh, who identified herself as one of Ms. Fairbairn's powers of attorney.
Ms. McCullagh wrote that her aunt would not be returning to the Senate in "the foreseeable future," Mr. Tkachuk said.
Reports on Monday suggested Ms. Fairbairn had been declared mentally incompetent in February, but continued to serve as a senator until the session ended in June.
Mr. Tkachuk said he and Senate Clerk Gary O'Brien have asked for documentation regarding Ms. Fairbairn's mental competency and sought legal advice on what – if anything – to do next. He said he isn't aware of any similar circumstances in the Senate and doesn't know if her powers of attorney would be permitted to make a decision on her behalf about her retirement.
Ms. Fairbairn, who will turn 73 this November, is two years away from the Senate's mandatory retirement age of 75. She grew up in Lethbridge, Alta., and worked in journalism before she was appointed to the Senate in 1984 by then-prime minister Pierre Trudeau.
She was an energetic and bright participant in Senate debates, Mr. Tkachuk said, adding, "Of course, as we would miss any senator, we'd miss her advice."
He said he's not in a rush to act on the letter.
"If anything is going to be done, it's going to be done with care," Mr. Tkachuk said. "My responsibility is to protect the institution, but at the same time have respect for the person who's affected by this thing."