Does the verb 'to be' have a direct object in English? And do all prepositions create a direct object too?

Question

For instance, would the correct sentence be 'whom is he?' or 'who is he?'?

Further, would 'to', 'for', 'with', and so on all be followed by a 'whom' or a 'him'; rather than a 'who' or a 'he'?

Thanks in advance!

Answer 1

In a comment, John Lawler wrote:

(1) Be does not have a direct object; Who is he? is correct. (2) Prepositions have objects, but not direct objects; only transitive verbs have direct objects. Also, some prepositions are intransitive and work on the side as adverbs or phrasal verb particles.