Forget the Giro. Him going to the Giro is essentially conceding his chances of
ever winning the Tour. I mean as long as he believes he is in decent form (among top 5 GC contenders) I think he will go for it. Imagine him turning up at the Giro being in spectacular form in the last week. He was never even able to test his "coming a bit undercooked" strategy (assuming that may be what he had in mind this year). He could turn out very strong - and blowing his last chance of winning the Tour.
As for the team - why would they ever want to give up the two-pronged attack strategy that worked so beautifully this year?
I think he will go for the Tour. And if he goes for the Giro that means he is in bad shape and won't win it...
P.S. I’m fully aware that by next year, should he decide to go to Giro, I will have forgotten my stance and expect he wins it