[Neil44]

My gut reaction is no. It does sound like a dumpster fire so I would leave. You feel a moral obligation to inform investors which is good but be open to the possibillity that there's more going on than you are aware of so things might not be as black & white as they appear in practical and moral terms.

[netsharc]

OP can probably start their email with "As far as I can see (and I may not be seeing everything)".

But as others here wrote, if the investor mentions the email to the CEO, it might trigger a witch hunt of who the whistleblower is. OP could say "I'm a former employee of [company]" and it would take the heat off people currently working there.