Tony writes, "My brother has legal status and has his own Social Security card. He also has a valid driver's license. He applied for a job and made up a SSN to hide his conviction. Can he get in trouble or can the employer have him arrested? Is that a crime or could he be in trouble? He really wants to work. Please help."
Legal immigrants must use their valid Social Security numbers to work: If he was convicted, served his time, and is now free, he cannot be arrested for that crime again. However, providing a false Social Security number and lying on Form I-9 when he starts working are criminal actions for which he can be prosecuted and in the future his application for, say citizenship, can be jeopardized, but if he get the job and the employer does not find out that his SSN is fake, he can keep working but would not be able to file taxes legitimately or claim a refund or if does that it will all be quite messy. If the employer finds out that he lied about his Social Security number (most likely if the employer does a background check on him chances are that inconsistent information would show up right away and the would doubt who he says he is), he might just fire him or call Immigration and report him as an illegal alien. In case ICE follows up on him (it seems that his previous crime was not a felony because then he would have been deported) nothing much might happen but it will get into his immigration file that he was working with a false SS# and that can come to bite him later.
Any abuse of SSN is a serious crime: As you are well aware he will be breaking the law if he did so and I cannot recommend you or anyone do that. It is indeed true that millions of illegal immigrants do that everyday and don't get caught but that does not make it right. The difference in this case is that he is not illegal and has a lot to lose because he is in the US legally (I am assuming that one day he would like to file for citizenship). Lying on a job application is a felony and if he gets caught he will just make things worse for him. A drivers license does not prove anything; it only allows you to drive a car and can be used as an ID. When applying for a job, he will either have to declare himself to be a US citizen or if he declares himself to be legal immigrant he will need to provide a copy of his immigration status. Maybe a small business will not check these things thoroughly but that would still be breaking the law.
American provides an opportunity to live the right life: The right thing for him to do is to find work in which his conviction will not disqualify him. That way he will go to sleep every night that he is doing the right thing and trying to start a new life the right way. Breaking the law yet again only perpetuates a cycle of lawbreaking and as his supportive brother you should help him end this cycle and put him on a path of living a good life.