But how is he having to show a household size of 2?? As we will not be living together, he will be staying with my parents?
You have to think in terms of long range plans. Is he going to live with your parents after you two get married? NO! Will either of your parents complete an I-134 stating that they will provide shelter during his initial stay while courting thier daughter? Will they offer to feed him while he is there? Will they list "Room and Board" on an affidavit or even just in a letter to him?