Can legal action be taken against a company who forces an employee to resign for being a convicted felon?

A friend of mine who is a registered sex offender applied for a job last August. Nowhere on the application did it ask about being convicted of a felony. He got the job and worked there for 10 months... The other day, a co-worker informed management of his record, and he was forced to resign. Can any action be taken against the company? Even though the application didn't ask about any felony's he may have been charged with, he did supply them with his social security number, so wasn't it the company's fault for not doing the background check using his social security number? He was already employed for 10 months, and his conviction was back in 2002, almost 10 years ago. All I know is he has come a long way since then, and has turned his life around. He was on his last year of registering for sex offender, and then he his record would be sealed....