I debated between putting "he" (gramatically correct) or "him". I thought about some real life examples and realized I and others in the U.S. would use "him" at least in casual conversation, even though grammatically incorrect. In writing, depending on my reader, I would probably use "he" some of the time. It is similar to the use of "I" or "me". For example, while knocking on a friend's door, "It's I", sounds very odd even though grammatically correct. I say and always hear others say, "It's me".