The weather was bad in the WC area yesterday, there was a large area of heavy rain which moved in during the morning.
Most of the GOM operators do, as B Sousa says, require instrument ratings but NOT so that pilots can knowingly fly into bad weather.
Weather minimums are strictly enforced and it just may be that the pilot of this aircraft got caught and couldn't get out. Both Airlog and PHI pilots are trained in inadvertant IMC using both the aircraft and simulators.
LE