So who pays the civil suit to the survivors of the victim, and who is charged?

the person sitting in the driver seat.

He can try and sue Tesla, but they will pull out a book of fine print on the FSD EULA.

I'd sue both if I were the family. The idiot for trusting and misusing the tech against it's eula and features, AND, the company so conceited they call it full self drive, suckering the stupids and creating accidents.

They're both equally culpable imho.

This was the big discussion back when I still worked in insurance while years ago. The discussion was that insurance companies would not accept liability for the owners of self-driving cars because its not the driver creating the risk, but the car company and its programmers, but that car producers would have to insure their own vehicles. The discussion was how the industry will have to adapt to survive this change.

Current models of insurance (and prices) is based on statistics, including the driver's age, gender, location, and characteristics of the vehicle (make, model, age). Some companies give discounts if you are willing to give them telemetry on your driving habits. (Personally, I'm not willing, but at least that's based on you individually rather than a statistical average version of you. )

Those all to out the window when the car is self-driving. Driving behaviour is determined by the competence of the programmers who programed the car, which is entirely opaque to the public and insurers. An update can totally change the driving behaviour anytime, in ways no one can know. That is not an acceptable risk to a risk-calculating industry.

When I was still around the industry, the current issue was exactly when did policy coverage start and stop for ride share drivers (the moment they accept a ride in an app or when a passenger enters the vehicle?). I have not seen a policy for a vehicle that has some autonomous mode, but I would imagine that, in these years since, wordings have been added that state a policy does not cover the owner when FSD is engaged. But I also haven't seen that car companies are actually offering insurance either.

So, owner or car company? Maybe both, but there's a reason that Tesla specifically states that drivers have to maintain control of the vehicle, for exactly this reason: to disclaim responsibility.