Very odd, considering no match of names, and no sources on the new profile. May be a mistake. You should be able to edit your mother's profile, and on the right side under the erroneous father, click 'Replace/remove father.' If it won't let you do it, the problem may be the false father's privacy setting.
I highly recommend that you go forward armed with documented information about the correct father. Could this be them?
"United States Census, 1930," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:XSYP-LDQ : accessed 5 July 2018), Jessie M Spangler in household of Ira Spangler, Field, Jefferson, Illinois, United States; citing enumeration district (ED) ED 12, sheet 8B, line 74, family 209, NARA microfilm publication T626 (Washington D.C.: National Archives and Records Administration, 2002), roll 521; FHL microfilm 2,340,256.