Nelleta,I found this on familysearch.org-search records-record search pilot.
Texas Marriages-1837-1973 Groom-I. F. Day Bride-Minnie Parker Marriage Date-July 18, 1899 Marriage Place-Henderson, Texas
This looks like Bonnie's siblings on the 1920 census information you have.
Guy Clarence Day Born-Jan. 15, 1902 Birthplace-Henderson, TX Parents-Isaac Frank Day and Minnie Bell Parker
Murt Dan Day Born-March 19, 1914 Birthplace-Henderson, TX Parents-Isaac Frank Day and Minnie Bell Parker
Elsie May Day Born-May 22, 1918 Birthplace-Henderson, TX Parents-I. F. Day and Minnie Parker
Texas Deaths-1890-1976 Izack Frank Day White Married Birth Date-July 27, 1879 BirthPlace-Brownsborough, TX Death Date-Dec. 27, 1937 Death Place-Sweetwater, Nolan, TX Occupation-Retail Furniture Dealer Father's Name-George Marshall Day Father's Birthplace-Alabama Mother's Name-Echols Mother's Birthplace-Texas
There is also a death certificate for a George Marshall Day-born April 2, 1875 died Henderson, TX(probably Isaac's brother)-it states his parents are George Day and Sally Echols.
You can also find Eugene Day's death certificate-it states his parents are Isaac Day and Minnie Parker.
You can find this information on findagrave.com
Isaac Frank Day-Born-July 27, 1880-Died Dec. 27, 1937 Minnie Belle Day-Born March 29, 1883-Died Oct. 23, 1966 Guy Clarence Day-Born Jan. 15, 1902-Died Jan. 7, 1988 Eugene Day-Born Dec. 27, 1908-Died Feb. 5, 1975 They are buried at Sweetwater Cemetery-Sweetwater, Nolan, TX
On the 1880 census for Henderson County, Tx you will find Isaac (spelled Isoak) F. Day age 10 months-it looks like he has a twin sister Alph 10 months. (their parents are George and Sarah Day)In the TX marriages you will find a marriage for a Miss Alpha Day in Henderson, TX in 1897.