Ah the pain of recovery and healing!

The PT's estimate is not outside the expectations even for "regular" orthopedic injuries. I have a neighbor; a healthy cross country/marathon runner who was told up to 3 years for full muscle return after a femur fracture.

The muscles of my affected foot have not beefed up quite the same as they were although it is strong on resistance testing and much better than it was. However, my nerve conduction study shows that the signal is compromised in the plantar nerves, so no surprise my foot muscles are not as "swoll". I was able to get my calves/soleus/tibialis measuring the same in under two years and strength seems to be about equal. I had a lot of atrophy from extended non-weightbearing but you can't see it at 2 years out other than the reduced signal foot (and even that looks way better). A lot of function has returned and I actually feel better if I work out. The endorphins and circulation boost help a lot of my symptoms. It's just finding the balance...

It took a year plus easily for me to feel that the myriad ligaments in my foot were up to par as far as flexibility and capacity to carry load. There is such a lot going on in there and the mechanical stresses being re-introduced can cause a fair amount of discomfort as the system remodels. This is where continuing with the gentle slow progression is so important. He'll know when he has done too much and should continue to listen to those signals. The gains WILL come over time. One day he will look down and his leg will look like the other one and you won't be able to pinpoint exactly when it happened.

I'm sure his PT will have a lot of advice for this exciting period. There are many little tricks used during rehab and some tips to be taken from a pure training point of view. ie: static stretches decrease muscle strength firing significantly for up to 30 minutes afterwards. (research done with EMG) This does not help muscle build. Dynamic stretch before exercise and static stretch after or at any other time. Testing for general muscle imbalances and tightness in the entire kinetic chain of the leg is also a good idea.

I highly recommend eccentric training methods such as eccentric calf raises. These strengthen the muscles and tendons with less loaded strain while stretching the soft tissues at the same time. They are often used in injury recovery to improve strength and reduce pain. So much is contracted after lack of use. He might like foam rollers or massage too. Anti-inflammatories are great as CRPSbe said. Myofascial work and stretching are also helpful. Just don't stretch too much too soon. All in good time. He'll be doing laps around all of us before you know it.