How you study and when is your business, not his. Given the importance to you in this instance of have only a weekend left before the PhD defense is expecially up to you. You will feel it out, going over the defense best you can, and then relaxing, resting.
I remember sitting in the room waiting to be called for my landscape architecture board orals and losing body temperature, ice cold hands. Then they called me in and I sailed through it. Prior to that, we had 3 days of national board testing exams. My husband supported my efforts but had nothing to do with how I studied. He did come with me for the orals, and waited. After I passed, we went out to a good restaurant. Before the meal, he ordered a good brand of Calvados, and I ordered Champagne. It was a good day.