Jimmy Osmond, 56, suffered a stroke during a pantomime performance of Peter Pan in Birmingham at the end of last year.
Now, Merrill Osmond, 66, who was previously the lead singer of the sibling’s group The Osmonds, has said a return to the stage for his brother is unlikely.
He commented: “I think they are off the cards. I think they are off, brother.
“We used to be called The Osmond Brothers. Now it’s down to Brother Osmond.
“It’s gone. The amount of health issues along (the way), it’s taken everyone pretty well down, except for Donny, Marie and myself.”
Merrill went on to say his brother’s illness is a “big enough disaster” to prevent him from performing again.
“He definitely needed space – and he still does. He doesn’t want to meet with anybody,” he added.
“The rest of the time it is basically family, and all the space he needs to get better.
“We’ve tried to stay around the details of it because he has asked us to not to get into details.
“But it’s a big enough disaster that he just needs to have his life and live it the way he wants.”
Merrill added Jimmy was “still refusing to see anyone but family at home in the US”.
Jimmy’s sibling went on to say he will continue to play his own music until “something happens” to him.
“I’m going to keep charging ahead, doing the things I love doing, and that’s music,” he added.
Back in December, Jimmy suffered a stroke as he played Captain Hook in the pantomime Peter Pan.
The singer fell ill on stage but still continued his performance and signed autographs for fans before being rushed to hospital.
Days after the incident, a source close to Jimmy said he was “comfortable” and receiving “self care”.
The source told the Daily Mail at the time: “He has received the care he needs and is looking forward to a few months of self care.”
A spokesman for Jimmy later told ITV: “On the evening of Thursday December 27th after pushing through the evening’s performance of Peter Pan at Birmingham Hippodrome, Jimmy Osmond was driven straight to hospital and diagnosed with a stroke.
“He is grateful for all the well wishes and will be taking time out in the new year.”
Jimmy and Merrill were a part of the famous Osmond family, who found fame in the 1970s.
Their string of chart-topping hits included Love Me For A Reason and Crazy Horses.