Yeah, but the odds are really good that it wasn't engine trouble. We have a whole lot of information, including airspeed, which did not increase before the crash as you would see with engine trouble. The NTSB report is highly likely to confirm the obvious.
The point is, I think the reason so many celebrities die in these kinds of crashes is that pilots get starstruck and do stupid things. A responsible pilot probably would not have taken off. 500 feet below a cloud, 1000 feet AGL in a congested area. Ceilings were 1100, don't take off. Granted, I'm not a rotary wing pilot, but I don't think it changes anything.
METAR said 2SM visibility which only goes to show don't trust them too much. You can't really have mist (BR) and 2SM viz at the same time. LA is famous for being a dangerous place to fly. Mountain obscuration, CFIT, fog, etc. They really weren't in the vicinity of the Van Nuys airport anyway.