Iva was obviously Blanch's sister & married late in life:

Name: Iva M McDermott
Social Security #: 566073175
Gender: Female
Birth Date: 23 May 1898
Birth Place: Kansas
Death Date: 2 Mar 1972
Death Place: Yuba
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directory
Name: Iva M McDermott
Gender: Female
Residence Year: 1948
Street address: 921 11th
Residence Place: Marysville; Yuba City, California, USA
Spouse: Joseph L McDermott
Publication Title: Marysville, California, City Directory, 1948