Explain whether using 'whom' is correct or not with educated grammatical reasoning.?

Question

I would like a grammatical explanation, please do not post anything like, 'I think it's xx' or 'who = subjective & whom = objective'.

Please also do not simply post grammar websites as I asked the question because I've read through and still am confused.

In the following sentence, 'whom' is being used:

A dinner was given in honor of the man whom everyone knew would be the prospective president of the company.

Please state whether using 'whom' is correct or not, and provide grammatical reasonings to support your answer.

I know about the objective/subjective view. However, what I need to know is 'how' to analyze this sentence to know whether to use whom or who?

I would like to see an answer that explains the choice with grammatical reasonings instead of a grammar website.

My confusion is due to the following:

Should the latter part of the sentence be read as:

Everyone knew the man. The man would be the prospective president of the company.

And therefore use 'whom' since the above can be translated as the following two parts: 'Everyone knew him.' 'He would be the prospective president of the company'.

Or

If it should be read as 'Everyone knew the man would be the prospective president of the company.' And in this case 'the man' can only be substituted with 'he', and therefore using 'who' would be correct.

I just need to know which analysis is correct.

Answer 1

It can only be the second analysis. You can't use a relative pronoun for two clauses, which is what the first analysis is doing. To mean what the first analysis means, you'd have to write:

A dinner was given in honour of the man whom everyone knew and who would be the prospective president of the company.