ailing

He has been ailing for several days.
他病了好幾天, 還沒好.

He was ailing (or ill) long before his death.
他死前久病纏身.
他病了很久才過身.
他生前一直抱病.

Nothing at all ails him.
他這人看得開, 天塌下來當被蓋.
他甚麼都不以為苦.