Taxes & Welfare Debate?

I'm curious my cousin in I are in a heated debate as to weather or not people who don't work can actually file taxes. Our argument doesn't include unemployment benefits, disability, ot even freelance but rather he's insisting that people on welfare can get huge tax returns and I'm pretty sure that is legally impossible. I was under the impression people had to fall over a certain low inome level just to be able to file taxes. And, no matter what people assume, I'm pretty sure welfare doesn't meet that level or even come close. I would like your all's opinions, also any proof backing them up. Thanks!!!!