It’s not permitted by a federal law to not have a base pay for commissioned employees. It’s typically low, minimum wages or even below like with wait staff. But having zero base pay is against the law. Federal labor law. It ensures fair labor standards. He needs to read his contract carefully.

I am sorry to hear that he has to work. So stressful. Income is good though. But I’d rather be safe. Double edged sword isn’t. Hope he takes precautions as much as he can