careless relative

What is the name of your state? NJ
I have a young relative living with me and recently found out he hasn't filled any federal/state income tax form since he started working at age 18 over three years ago! He also has collected untaxed unemployment benefits for about 6 months. His status is single without dependents. Now he's concerned about the consequences and penalties of his negligence at the time of filling or later on. What are his choices?

It's a fact they will eventually catch up to him. The best he can do is notify the IRS that he hasn't ever filed, plead ignorance and hope for mercy.

He really doesn't have any choice.

Just file the tax returns.