Let me ask another silly question. Does 'other than' take the subjective, or objective case, or does it depend? In short, is 'other than she/he etc.' grammatical (or can it be)?
1 Answer
"No one knew the answer other than he" is grammatically correct.
"He knew the answer" is correct, and therefore using "he" in the first expression you give here is correct too ("... other than he").