20yr loses $700k on Robinhood options, takes life

My cousin in law was interested in investing. He opened a Robinhood account. And, he seemed to be enjoying the markets. As many of us do, or have done, he got interested in options. He believed he had “no margin” selected on his account.

So, he began buying and selling options. Fast forward to sometime this past week and his account showed him owing $700k+. How does a 20 year old with no income get access to that kind of leverage/exposure?!