Why did they have to replace the plane if the problem was the pilot? Just ship another pilot to Canada to bring the plane home. They are still going to need to move the plane.
There seems to be some holes in the official story.
The aircraft involved, one of the carrier’s 43-strong fleet of Boeing 777-200ERs registered G-VIIP remained on the ground in St. John’s for about 36 hours before continuing to Gatwick on March 16, 2024, taking four hours and 18 minutes to return to its base airport. The aircraft has since completed rotations from Gatwick to Tampa (TPA), Bridgetown (BGI), and Orlando (MCO.
Its base airport is Gatwick. I'm sure you know where that is.
No, there are no "holes in the official story". The aircraft being a Boeing product has nothing to do with the pilot falling ill.
I'm not going to flame you for your comments (this time), but I will note that you deserve a thorough flaming for them.