What does Adam–God show about prophetic reliability?

The 1852 text is a sermon report, so I’d check whether anything else corroborates the key wording.

That is a good check. Woodruff’s same-day journal and the 1873 newspaper report provide evidence outside the original published sermon.

Yes. Woodruff’s journal corroborates the core teaching, and a later newspaper report records Young repeating it and claiming revelation for it.

You acknowledge the limits of a sermon report and bring in independent evidence. The repeated teaching makes a single transcription error an inadequate explanation.

Those are two different claims. Doctrine and Covenants calls Adam Michael. In Moses 6, God speaks to Adam about Jesus as His Only Begotten Son.

You distinguish a title the canon applies to Adam from the identification Kimball rejected. Moses 6 gives a direct textual comparison.

I’d set aside both claims because Kimball denounced Adam–God.

Kimball rejected the theory. The canon still identifies Adam as Michael. Check which specific claim each source makes.

I would point out that Adam–God was never canonized.

Formal adoption is a distinct question. Your friend is asking about trust after a public claim of revelation, which still needs a direct answer.

That gives me reason to reject this particular claim. It also tests any idea that every prophetic claim is guaranteed. I’d weigh the other evidence before drawing a verdict about the office itself.

You grant what the record establishes and name the extra step needed for a wider conclusion about prophetic authority.