Yea, but what device draws that much power. In the us, most space heaters are 1200w, so about 10 amps. So he’d need to really have a high load device. You might be able to find some 30amp single phase loads.

Putting them all on their own circuit does so much to actually protect him unless he has various extension cords or those 2 receptacle to 6 receptacle devices.

For 500 amps, he should be running 1000 gauge wire. Which would be so impressive to run since each leg would be almost an inch and a half thick and $50 a foot. Each breaker would be over $2k, if he went with the cheapest 500amp breaker.