Do you believe God is in ultimate control of His created Universe? How do you measure 'ready to be called home'? Who calls them home? Are humans so powerful now that they can counter the 'call'? ... Really?
A) There is zero chance the person will recover from the illness that will ultimately kill them.
B) Their physical & mental condition has deteriorated to the point they can no longer move, speak or eat on their own.
C) The sole reason they remain alive is because the law requires it & medical staff complies.