Has the Ponzi family sued the US Government for using his idea.
Not yet.
Deportation to Italy -- On September 28, 1927 with Ponzi still in a Massachusetts prison, the Immigration Bureau issued a deportation order for Ponzi. The warrant, however, would not be executed until he was released in 1934. The basis of his deportation order was a federal law that allowed deportation of individuals having been convicted of a crime involving moral turpitude. Ponzi challenged the order, claiming that moral turpitude involved a crime against chastity, and did not apply to his larceny conviction.
Mrs. Anna C. M. Tillinghast, United States Immigration Commissioner for Boston, replied in a letter that turpitude was "an act of baseness, vileness or depravity in the private and social duties which man owes to his fellow-men or to society in general, contrary to the accepted and customary rule of right and duty between man and man." Another writ of habeas corpus was denied on June 3, 1932.
On February 14, he was released from Massachusetts prison and arrested by federal authorities as an undesirable alien. Having exhausted his funds, he was unable to raise bail. Ponzi appealed the Immigration Bureau's ruling to the Federal District Court in Boston which upheld the deportation warrant on July 30, 1934. He left the United States for Italy that year.
In July of 1935 he requested permission of the United States consulate to visit the country, and in September of that year he was reported to have been hit by a truck in Italy, receiving only minor injuries.
Authorities may have been concerned that Ponzi had not abandoned his love for the Land of Opportunity. In September of 1939 the FBI interviewed a California man but concluded that he "did not resemble the photograph of Ponzi in any respect."
Ponzi emigrated to Brazil sometime before World War II. The dates here are vague, leaving room for conjecture as to his activities and country of residence in the late 1930's. Nearly destitute when he arrived in Brazil, he eked out a living teaching English, receiving unemployment compensation in slack times.
He reported this most ambitious scheme was an attempt to swindle the Soviet Union out of 2 billion dollars by promising to smuggle gold, adding: "What a joke on the communists that would have been."
His declining years brought infirmity, with paralysis on his left side and partial blindness. He spent his final days in the charity ward of a Rio de Janeiro hospital, and died on January 15, 1949 at the age of 67. A legal agent claimed Ponzi's body and buried him using $75 Ponzi had saved from a Brazilian government pension.