Sister Helen Marie Evert, S.S.S.F., who taught at St. John the Evangelist School in Beacon, died May 18 at St. Joseph's Convent in Campbellsport, Wis. She was 87. Sister Helen, who formerly was known as Sister Gregoir, taught at the Beacon school from 1964 to 1973. She also was a teacher, principal and tutor in Wisconsin and Illinois. Born in Howells, Neb., she entered the School Sisters of St. Francis in 1937 and professed final vows in 1939. She is survived by a sister, Liz Zila. A Funeral Mass was offered May 22 at St. Joseph's Convent, with burial in the sisters' cemetery there.