When a modern aircaft like this has an electrical failure I would feel very uncomfortable.

He also lost part of his displays during conditions with little sight.

So imo the question should be if it would have been possible for him to check if the airplane is really out of control, in a way that it wouldn't cost his life if it was.

If his standby instruments were operable, the answer to that question is likely "yes." Having not flown a STOVL aircraft, the only part I can't speak to is whether his thrust vectoring/lift fan was in an unknown configuration, and how that plays into things. But generally out-of-control flight results from a spike in angle of attack at low speeds leading to aerodynamic stall and departure, and modern fly-by-wire aircraft are highly resistant to this.