Why is gregor allowed certain new privileges at the outset of Chapter 3?

Gregor's injury cripples him so that he finds it difficult to move around and can no longer climb walls. As a result, however, his father realizes that Gregor should be treated as part of the family and not as an enemy, and the family now leaves the door to his bedroom open so that he can watch them sitting around the table while he remains hidden in the dark.