I suggest you go to ancestry.com. If you are not a member, you can sign up for a free 14 day trial.
On ancestry, I found the following, which may or may not be what you are looking for.
There is a California Death Index record for a Daniel Peter Wynn, born 09-18-1913, in IL, died 07-27-1987, in Los Angeles County, CA.
Based on that record, there is also a Social Security index record for a Daniel Wynn, born 09-18-1913, died 07-1987, last benefit to Huntington Park, Los Angeles, CA, state SSN issued is IL.
Using that year of birth, on the 1920 US Census, at 1368 W Dean St, Chicago, IL, there is a Daniel P Wynn, age 45, born in IL-IL-England, works as an officer for an electric company, with wife Barbara, age 36, born Russia-Austria-Austria, with children John, age 13, Barbra, age 8, Daniel and Rosy, both age 6 and Thomas and Roy, both age 3, all born in IL.
On the 1930 US Census, address unreadable, Chicago, IL, Daniel is age 60, born in NY-NY-NY, works as a watchman for Western Electric Co, with wife Balbina (?), age 47, born in Poland-Poland-Poland, with children John, age 23, Balbina Jr, age 18, Rosalie and Daniel Jr, both 16, and Roy, age 13, all born in IL.
There is a World War I draft registration card for a Daniel Peter Wynn, born 12-06-1877, living in Chicago on Paulina Street, working as the Sargeant of Police for Western Electric Co., with wife Barbara.
So, if the son mentioned on the 1920-1930 census, Daniel Jr, is your father, then his parents are Daniel Peter and Barbara (or something similar), and he had a twin sister named Rose (or similar) and other siblings named John, Barbara (or similar), Thomas and Roy (also twins).
Since son Thomas is on the 1920 census, but not 1930, I looked him up and found a Cook County Death index record, giving his name as Thomas P Wynn, born 01-30-1917 in Chicago, died 11-08-1921 in Chicago, buried 11-10-1921 at St Adalberts Cemetery (Chicago), age 4, father Daniel P Wynn, born in NY, mother Barbara Tryhur, born in Poland.
Hope this was of some help. If these are the right people, it shouldn't be too dificult to find more.