Unfortunately, currently Freestyle doesn’t have an interface that can choose imperial units display in decimal format (e.g. 1 1/4 to 1.2500).
Having said that, you can suggest this feature at Freestyle wish list, where you can see and vote for suggestions made by other AutoCAD Freestyle users
https://autocadfreestyle.autodesk.com/wishlist
Avto Chachava
Autodesk Product Support
Autodesk, Inc.