McCain has shown what a fighter he is. I wouldn't put it past him to hold onto life until the traitor is out.
I doubt that will happen. My experience lately is that by the time hospice is called in the person has only a matter of days or, at most, a couple of weeks left to live.
Impeachment, on the other hand, will take months.
Besides, since Sen. McCain wouldn't be available to vote to confirm (or not,) Kavanaugh, there would be a much better chance to deny him confirmation.
He also voted against the ACA. Not sure what that would have to do with Kav anyway. McCain even voted against a re authorization of SCHIP. There is no whitewashing this guys voting history.