Seed and Series A is investment in the people always. They assume if the product doesn't work the team will pivot until they find something that does. It sounds to me like your friend failed to pivot when needed.
Not even. I'm seeing seed and series As/Bs on unproven teams of recent graduates with no experience in the field where the "start up" operates. No business plan, no prototype, huge regulatory walls to climb.
Funds make money on failed investments too. I'd be happy to throw away someone else's money, if I got to keep 20% as a management fee - and a slice of the profits in case one of my lottery tickets is a winner.