How to heal my broken ankle?

Hello doctor,

My partner, who is 36-year-old, broke his ankle (fibula break) before 7.5 weeks. I had been for his appointment where he had an x-ray and found that the bone has not knitted together. He smokes approximately 10 cigarettes per day. I have found through online research, that smoking hinders bone healing and have advised him to stop, even if short term to assist with the healing of the broken bone. He had a cast for three weeks and then was transferred to a walking boot with vague instructions on how to deal with it. He is being told that he should be walking more on the ankle which is broken. But, he is worried as he will cause more damage as it is not yet aligned. Also, should he be wearing his walking boot at all times? He wears it while sleeping and he removes it while bathing daily. Please explain to him how the bone will heal and whether he should be wearing his boot all the time.