Former Fiat Chrysler CEO Marchionne in grave condition

July 23 (UPI) -- Sergio Marchionne, the longtime former chief executive at Fiat Chrysler Automobiles, is in grave condition just days after he was replaced, medical officials said.

Marchionne, 66, has been in a coma at a Swiss hospital since Friday, when he experienced complications from should surgery last month.

His condition may be "irreversible," according to Italian newspaper La Stampa.

FCA Company Chairman John Elkann wrote a letter to employees after the appointment of Mike Manley as Marchionne's replacement.

"It is with profound sadness that I must tell you that the conditions of our CEO, Sergio Marchionne, who recently underwent surgery, have unfortunately worsened in the last hours and will not allow him to return to FCA," Elkann wrote in the letter, La Repubblica reported. "Sergio was the best CEO you could wish for and, for me, a real mentor, a colleague and a close friend. We met in one of the darkest moments in the history of Fiat and it was thanks to his intellect, his perseverance and his leadership if we managed to save the company."

Marchionne, who'd been Chrysler CEO since 2009, hadn't originally planned to leave the company until early next year. Manley was appointed to replace him Saturday.

Prior to the complications, Marchionne had expected to leave the hospital within a few days of his surgery and had confirmed his agenda for early July. He had also recently announced a strategy to boost company profits and global sales volume through 2022.

"Mr. Manley and his management team will proceed with the implementation of the 2018-2022 Business Plan as presented on June 1 of this year, a plan that will further assure FCA's strong and independent future," a company statement said.

Marchionne visited the White House with other auto executives in January 2017 after President Donald Trump took office.