If you haven't looked at the 1940 Federal Census for Ohio, I suggest you do so. There is additional info on James (the father) at the bottom of the page. You can easily find the page free at familysearch.org. I entered your grandmother's name to find it.
The additional information says James had a Social Security Number. I have never ordered a copy of a SSA application. Ask other people if it's worth the money.
Also, Mamie's death certificate is on familysearch site with her name spelled Mammie Idella Love. If you have any problems accessing these records, please email me & I'll try to describe how to get to them.
I am not related to these Loves. Alice Cobb firstname.lastname@example.org