And you know all this how? If you obtained this information by illegal means, you yourself could face prosecution and/or a lawsuit. And, if you are basing this on belief and assumption only, you could face a lawsuit for libel and defamation.
The statement above is general in nature, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship.
How on earth did you obtain these information about someone else?
If he works, pays taxes and claims child tax credit, is that tax fraud?
This is a duplicated question. Since this is not you, one wonders why you care. If he is here "illegally", he cannot be legal. Often aliens use a TIN to pay taxes which may or may not help them with citizenship down the road. This should be posted in immigration for a better answer.
If you liked this answer, click on the thumbs up! Thanks. Eliz. C. A. Johnson Post Office Box 8 Danville, California 94526-0008 Legal disclaimer: I do not practice law in any state but California. As such, any responses to posted inquiries, such as the one above, are limited to a general understanding of law in California and not to any other jurisdiction. In addition, no response to any posted inquiry should be deemed to constitute legal advice, nor to constitute the existence of an attorney/client or other contractual or fiduciary relationship, inasmuch as legal advice can only be provided in circumstances in which the attorney is able to ask questions of the person seeking legal advice and to thus gather appropriate information.