Seeking next steps for mother's eligibility

Hi, I'm trying to help my mom do some research to determine if she is eligible/next steps for her Italian citizenship. Her dad was born here in the United States in 1921. Her grandfather who is born in Italy, began his naturalization process in 1920 and was officially approved for naturalization in 1924.

We have the paperwork showing the naturalization and her dad's birth certificate.

Does she qualify and what would happen next if she does?