I wonder how much time Chris has been in coma. He was hit at the head by a bullet but his brain was spared (if i remember, they said that the wound is only exterior) (which is good, i'm not sure they could have done anything if the wound had been actually deep and touched the brain, Chris would have died)
but he has been unconscious for a long time and had still crutches when they find Emma.
So it mean that his awakening was "recent" if he still needed crutches (so reeducation).
How severe was his wound? for how much time was he in coma?
Have you theories about it?
Fun fact: Chris was originally supposed to wake up during the Seven Walls arc.
(Mystic Code Book Chapter 5)
But yeah after they arrive at the paradise hideout his condition is "conveniently stable" so Shirai could utilize it to facilitate more drama if he needed to or just keep it as is, and he ended up going with the latter.
(Chapter 126 | Mystic Code Book Chapter 7 Series Timeline)
We don't know the exact date he was shot, but he spent roughly half of October 2047 and at least thirteen days of November 2047 comatose.
After that, it's arbitrary, even if one wants to be canon compliant.
If you want it to take a while for him to wake up, the explanation can be Peter wasn't careful while transferring him from the paradise hideout to Grace Field headquarters, and Chris suffered brain trauma they weren't aware of until they did tests at a hospital.
If you want him to wake up shortly after they arrive in the human world, like in one of Shirai's drafts of chapter 179, you can still have his recovery span the course of months since muscle atrophy occurs rapidly.
(Mystic Code Book Chapter 6; I would have been up for this version)
(Muscle Atrophy in ICU Patients article)
You can also prolong his recovery further by introducing a psychosomatic component. In addition to the physical harm that befell him, the mental trauma of the bunker raid resulted in a combination of him not waking up for however long one wishes to keep him in a coma and possibly hampered his physical therapy for months to over a year even after working to rebuild all the strength he lost.
There are a lot of ways you can adapt it to fit within the phrasing presented by the kids when explaining their trip to Emma in the epilogue:
"Able to walk again" meaning it did take him some time, although we never see him using crutches like Dominic or Sonya.
(Chapter 126 | Chapter 157 Bonus Sketch | Chapter 98)
Also it's never focused on, but Sonya uses a cane like her dad post-timeskip.
(Chapter 104 | Chapter 106 | Chapter 111)
