Minimum wage is not meant to support a family
Personally I including having a family in a "decent living", and given the standards of the 1930s where women were generally expected to be homemakers I doubt Roosevelt intended this quote to suggest two working parents.
I realize that a segment of the population has been working to redefine the minimum wage and what it's for, telling us that it's for teenagers who don't need a living wage, but let's be clear: at it's inception minimum wage was supposed to provide a family a comfortable living.
If that were true, it would be legally specified as "the minimum wage you can pay to someone without a family."
Minimum wage was always intended to be a living wage. It just hasn't kept pace with inflation for the last several decades.
There is absolutely nothing that makes it harder to pay someone with a family minimum wage, or easier for someone with a family to get a job with a better wage.