I have found immigration records for a Franz Helfert, born about 1900, who arrived into New York in 1923 and 1931, both times indicating he was born in Czechoslovakia (village name Alt Pohlau). The 1931 record indicates he is single, bound for his own home 1253 Lexington Avenue, New York. Gives his brother, Ernrst Helfert in Alt Pohlau as his next of kin at home. The 1923 record indicates he is married; gives his wife, Ella, in Carlsbad, Czechoslovakia as his next of kin; bound for his brother-in-law, Franz Liszka, 515 Second Street, Washington, DC.
A third record, as Frank Helfert, in 1939, gives the same village, spelled this time as Alt Rohhau; he is married and travelling with his wife, Olga, who is Swedish. He is a gardener by profession. Bound for his own home, 177 Bergen Street, Brooklyn.