"It would include the parent's home for the first part of the year and whatever household expenses (rent and utilities?) the child has after college through the end of the year."
I don't think we know whether the grandson is still living with his parents or has moved out to his own place, or will move out before the end of the year. I don't recall any mention of where he is living now. Maybe he doesn't know himself whether he will move out before the end of the year, or how much it might cost. Another unknown!
