They don't need him. The Switzerland game and a few games he missed previously made that clear. He won't like it though and Santos will have to work a plan to minimize the damage to the team. It is clear that Santos understands Ronaldo is done, but also knows he has to handle carefully. I would be surprised if the FA forces Santos to reinstate him. That would mess things up inside the team.
For the other teams still in the tournament, it would be good that Ronaldo plays as much as possible though and from a record point of view, I would like to see Ronaldo reach 200 caps, but he doesn't need to win the World Cup for that.