Ratroddad, your moms bike looks like it could be a Hawthorne or maybe a Colson of about the late 30's or the early 40's. You know sense girls were not the primary target of bike company's it's hard to find good pictures. The head light looks like a Delta and the tank look to have a horn, but I can't tell if the back fender had a skirt gaurd on it or not.
The tank tells me you don't have a Schwinn becauce of the flat edges. The shape and the design of the tank says Hawthorne. If only the head badge was a little more clear.
I have the book ( Collectable Elgin - J.C. Higgins & Hawthorne Bicycles)by James Hard & T.A. Gordon
Good luck hope you find out
P.s. I have a girls Rollfast and it's tank is a lot like the one in the picture, man, I wish I had a way to send pictures!