Can he be an object pronoun?

I understand that a sentence can have more than one subject, but I don't understand the grammatical role of he in the question below and which verb he is performing if he is also a subject.

Who is he?

My understanding is that the above question is a request of information, and hence, the implied recipient of the question, you, is the subject pronoun. The question, when presented explicitly, would be as follows:

Who (do you think) is he?

If my assumptions are correct, wouldn't that make he the object pronoun, since the subject you is performing the verb think on the object he? However, I read online that him is the object pronoun, not he, so I can only gather that my assumptions are wrong, somehow.

And if they indeed are, that would mean the implied you and the pronoun he are both subjects and he is performing the verb is, but I am not sure.

Please enlighten me if you understand what I am asking. It is much appreciated.

Solution 1:

He is a subject pronoun in Who is he? The question has subject-auxiliary inversion; it it asking the listener to fill in the blank in the corresponding uninverted statement He is [noun phrase]. E.g. "He is [my brother]" or "He is [the friend I told you about]." It's the same sort of structure as Where is he?

A piece of evidence that he is the subject is that when the pronoun after the auxiliary verb changes, you have to use a different form of the auxiliary verb: Who are they?, Who am I? English verbs agree with their subjects.