More than a few bob, if the Basler Zeitung is to be believed.
They worked out he's booked for 34 dates between mid-July (his planned comeback date) and the end of the year. His fee, they say, is 15,000 to 20,000 euros a night.
Which means he's on to make around 500,000 to 700,000 euros for less than 6 months work. If he's fit to perform, that is.
On top of the more obvious benefits, taking a few months off to optimise his vocal health looks like a smart business decision.