MPN11
The aircraft took off with an unqualified pilot in to IMC conditions flying a paying passenger ( someone paid ) there was no AoC in place. The flight was in a single engine piston over water at night and there was no legal way to make the flight under the rules of the state of registration....... and now we find out that it is very likely both the pilot and definitely passenger had enough CO inside them to incapacitate them at the very least.
Are you surprised that the maintenance is called into Question ? His whole sorry affaire seems to have left no rule unbroken from an operational point of view, perhaps its time to look at the maintenance as well.