I cant understand why anyone who has had a fractured femur wouldnt require some help with exercises and restoring normal function! You should insist on some help. With your fracture being reasonably close to the knee the joint was very likely to be swollen inside your cast. The exercises you should do will depend on how much flexion movement you have.

A physio should show you how to do good quadriceps exercise and how to stretch. It is quite normal for your whole leg to take a while to get back to full function.