Can1500w inverter or Honda 2k gen work 900w Microwave

My brother now says he isn't sure if he has run the microwave off the generator now. He's been in full hookup CGs a few times. Not much dry camping since Covid. So the Honda 2200i must be able to handle the microwave. It's just the GoPower 1500w inverter. GoPower wants him to do some tests tomorrow and give them a call back. I will be able to check it out tomorrow afternoon at the CG. I have the devices to do so. I bet he has something drawing extra power from the inverter.