By the way, if you need examples of other guys whose voices have suffered because of smoking - here goes - Joe Elliot (def leppard) started smoking 1995 - last album much lower vocals although he still puts effort in live (to some success).
Bono - although still with power he no longer has that huge range and effortless sound (listen to the Joshua Tree compared o the new one)
Bob Dylan - need I say more (if he everhad a voice!!)
We must all give the oompas and ask the band grief about his voice - MAYBE somehow a message may get through that we are not all stupid and want him back to his best!!