I'm not saying it happens ALL the time, but just last week I come across a newer Hyundai full engulfed on my way home. I know that's just one example, but again it can happen to anything.
Welcome to the forum, I find this statement funny (Sorry). He's right, it should not have caught fire, but it sounds like it did.
Keep us updated on what they say.. fires happen all the time on any brand. It's just not uncommon.
Welcome!
Like Brady said, find a clean one and enjoy it. If it's out of powertrain warranty, I would most definitely say get an extended warranty and make sure it covers major components incase of a failure.