Hi Swimtime,
I have to say the weightbearing thing sounds a little scary to me. How much like swiss cheese are we talking with those holes? My concern would be deviating from what is known about laying down new bone and preventing fracture.
I wonder if there is a happy medium in here like Bio suggested. There are multiple ways to deal with this. I can understand having boot pressure on the anterior ankle incisions being uncomfortable. Do you have a rolling walker at home? I used mine post-op to partially weightbear by supporting much of my weight with my arms. I wore a surgical shoe for this and it is much less cumbersome. If the goal is CRPS prevention he may not really need to be putting all his weight on that foot now to get benefits of pressure feedback.
Free movement may help as much as anything, so starting whatever gentle ankle circles, alphabet, etc. is allowed. They don't have to be full range in the beginning.