That is one thing he or his handlers cannot do. He must be physically on the Senate floor to vote.
I did a special report on congressional officials voting on legislature and appointments. They MUST be present in the house or senate floor. Durban told me tbeyve gadpeople rolled in on gurneys to cast a vote.
I wouldnt be surprised if McCain is flown by air ambulance to DC to Voteagainst President Trumps nominee, for this.