with all due respect, this is becoming more like the implausible witch hunt every post?
from what is known, the EC135 has multiple warning systems for fuel, on different displays, some with audio alerts too.
it's just not credible that *all* these systems failed - but only in respect of telling the pilot his fuel situation.
if the displays had 100% failed, would it not be prudent for the pilot to have just bailed out and landed ASAP rather than push the position (in mind he is already close if not over the endurance of the initial fuel load, flying in the dark and now instrument blind?)
Look, nobody wants to point the finger especially as he is not here to defend himself, but to try and cook up wildly implausible reasons to explain it is not helping anybody.