The actual rating for a 30-amp Powerpole is for a 30° Celsius (54° Fahrenheit) temperature rise at 30 amps (and 110 volts) using 12-gauge wire. This temperature rise spec is published in the National Electrical Code for building wiring and is more of a wire gauge rating than it is a connector rating. The power level noted in that standard is 3,300 watts.
Using Anderson Power Pole Connectors, Del Shier
I don't suppose your friend posted pictures? Is it possible he had a bad crimp, or misdiagnosed the failure? Seems like a big disparity to fail at less than a 1000 watts when they are rated for over 3000 watts.