It's probably just not the right context for introducing this topic.

The suggestion that a fast might have cured this person's alcoholism and saved their life is highly speculative and may be seen as offensive by some.

Offensive really? Is it part of the American culture? Genuinely curious.

Nothing to do with American culture - I'm not American. It's about speculating about what might hypothetically have prevented the death that we're talking about, when we have absolutely no idea what was going on in that person's life, hence we're in no position to speculate.