A warrant does not expire with the passage of time. The only possibilities, are that he addresses the underlying charges and warrant by returning to the country; or, hopes that the case gets so old that the prosecution finally deides to seek a dismissal of the charges and warrant. There may be additional facts not listed in your question that could aid in determining the best choice of action, and if so, I suggest that you consult with an experienced criminal defense lawyer admitted to practice law in NY. Good luck.
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Mr. Bailey is correct that a warrant, particularly a felony warrant never goes away. More importantly, it may get picked up by Customs when your uncle tries to come back into the country.