We're so sorry to hear this. Donny Osmond and Marie Osmond have asked their fans for "thoughts and prayers" for their older brother Tom Osmond, 70, as he remains on life support after undergoing quadruple bypass surgery on Saturday, July 7.

"As you may know, my brother Tom underwent quadruple bypass surgery on Saturday. He is on life support right now and fighting to hang on. It's been an emotional and challenging few days for all of us, so I hope you'll understand the radio silence from my end," Donny, 60, captioned a sweet throwback photo of himself with Tom on Instagram.

"We don't know what the future holds for Tom, but it's in the Lord's hands now. The whole Osmond family would appreciate your thoughts and prayers on behalf of my sweet brother," he continued in the Tuesday, July 10 post.

Donny and Tom's sister, Marie, 58, also took to social media to ask for prayers for her sibling. "Despite his physical challenges, my second eldest brother always strives to remain upbeat. This passage describes him best: 'Let my soul smile through my heart and my heart smile through my eyes, that I may scatter rich smiles in sad hearts,'" she wrote alongside a snapshot of herself with Tom.

"Tom is so full of life and love! I’ve always seen his enthusiasm through his Christ-like [heart] and he definitely shines LOVE trough his eyes. He just has a way of warming hearts with his big smile and tender hugs. But this weekend, love and prayers go out to Tom, his wife Carolyn, their children and grandchildren, as he struggles on life support from a quadruple bypass surgery," Marie continued.

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Despite his physical challenges, my second eldest brother always strives to remain upbeat. This passage describes him best: “Let my soul smile through my heart and my heart smile through my eyes, that I may scatter rich smiles in sad hearts.” 💜 Tom is so full of life and love! I’ve always seen his enthusiasm through his Christ-like 💖 and he definitely shines L❤️VE trough his eye’s. 🤩 He just has a way of warming hearts with his big smile and tender hugs. 🤗 But this weekend, love and prayers go out to Tom, his wife Carolyn, their children and grandchildren, as he struggles on life-support from a quadruple bypass surgery. 🙏😞 He has such great love for all people, including strangers. His ♥️ is so tender that at times, I swear, it even breaks when he sees others struggling. I love him for that! Maybe because he was born deaf and through some of the heartbreaking challenges of his life, they have given him great compassion and personal understanding to know how to comfort others! I am saddened though about my dear brother’s condition. Please join us in 🙏  See more on my Facebook and MarieOsmond.com/SundayMessage I love you with with all my 💞 my sweet brother Tom! You are so cherished and loved!!! 😘 ❤️ 💜 🧡💛💚 Have a blessed and #Happy #Sunday! 💋 #HisDay #BecauseOfHim #HeLives #resurrection #brokenheartandcontritespirit #PrayersForTomOsmond #hesmybrother

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"He has such great love for all people, including strangers. His [heart] is so tender that at times, I swear, it even breaks when he sees others struggling. I love him for that! Maybe because he was born deaf and through some of the heartbreaking challenges of his life, they have given him great compassion and personal understanding to know how to comfort others! I am saddened though about my dear brother’s condition. Please join us in [prayer]… I love you with all my [heart] my sweet brother Tom! You are so cherished and loved!"

Tom is the second eldest Osmond child and occasionally performed on his famous family's TV specials in the 1970s and 1980s. The other Osmond siblings include Virl Osmond, 72, Alan Osmond, 69, Wayne Osmond, 66, Merrill Osmond, 65, Jay Osmond, 63, and Jimmy Osmond, 55.

tom osmond virl osmond

Tom (left) with his older brother, Virl.

Tom himself is a father to nine children: Matthew, Benjamin, Geoffrey, Anmaree, Amelia, Anna, Mathew, Thomas, and Jennifer. He had five kids with his first wife, Lyn Heslop, whom he was married to from 1972 until 1989. Tom and his second wife, Carolyn Olsen, 57, tied the knot in 1989 and are parents to four children — two of whom were from Carolyn's previous relationship and Tom adopted — together. Our thoughts are with the entire Osmond family during this difficult time.