Hallo Bertil,
Using the information that you have given, I have found some information that may be a reasonable guess but I cannot confirm 100% if this is the correct Beatrice. But the surname Sonnenschein is not common so this may be the correct Beatrice.
In the 1930 Census, Beford Township, Westchester County, New York:
Beatrice Sonnenschein, age 19, born in New York, parents born in New York; inmate at the New York Reformatory Prison for Women in Bedford Township, Westchester County, NY. Her occupation was listed as clerk in a store (which is probably what her occupation was before going to the prison).
**This reformatory prison was, at the time Beatrice was there, a place where women went who were convicted for misdemeanors. See link about this prison: http://www.archives.nysed.gov/a/research/res_topics_legal_corrections_inst_bedford.shtml
1920 Census, Bronx Borough, New York:
-Percy Sonnenschein, age 34, born in New York, father born in Austria, mother born in New York, occupation of clerk in an office
-Carry Sonnenschein, wife, age 33, born in New York, father born in Hungary, mother born in Hungary, no occupation
-Beatrice J. Sonnenschein, daughter, age 9, born in New York
-Blossom I. Sonnenschein, daughter, age 1 year and 6 months, born in New York
-Irving E. Black, brother-in-law, age 24, single, born in New York, parents born in Hungary
-Sallie Black, sister-in-law, age 31, single, born in New York, parents born in Hungary
So, it appears that Carry (probably “Carrie”) has her brother and sister living with the family and that her surname is “Black” (which is probably an Americanized surname since both parents came from Hungary).
If this is the correct Beatrice then it is now fair to say that Beatrice was born in 1910 in New York, daughter of Percy Sonnenschein and Carrie Black.
Again, assuming that this is the correct Beatrice Sonnenchein, with Percy and Carrie as parents, then this article in the Long Island Daily Press, dated Thursday, January 4, 1934:
“22 Couples Attend St. Albans Reunion
Twenty-two couples attended the annual reunion of members and friends of the Jewish Center of St. Albans, held at the home of Mr. and Mrs. Percy Sonnenschein, 191-62 115th Road, St. Albans, on New Year's Eve. Mrs. Alma Mayer, auxiliary president, was in charge of arrangements. Among those present were Mr. and Mrs. Abe Mayer Sr., Mrs. A. Mayer, Mr. and Mrs. Murray Olyphant, Mr. and Mrs. Sam Hyman, Mr. and Mrs. Sidney Fox, Mr. and Mrs. Martin Herzog, Mr. and Mrs. A. E. Levy, Mr. and Mrs. Harry Gohlson, Dr. and Mrs. C. R. Rosner, Mr. and Mrs. Charles Goldwater, Mr. and Mrs. Louis Haas. Mrs. Jean Falk, Mr. and Mrs. P. Sonnenschein and Rabbi Julius Kerman. The group will soon hold a theater party in Manhattan. Murray Olyphant is in charge.”
The questions for your wife’s father are:
1) Has he ever heard that his mother’s family may have been of Jewish ancestry?
2) Has he ever heard about his mother having a younger sister?
3) Does any of the above information remind him of some fact about the Sonnenschein family, like what month was his mother’s birthday?
4) Are the names of his brothers Charles and Robert?
5) Does he remember if his father was born in Canada and was much older than his mother?
I hope that this is the correct information and, if so, there is much more available on the Sonnenschein family.
Gr,
John