Would dry fasting heal brain damage ?
Wow. Brain damage/TBI is a big spectrum and packs a lot of baggage. All the usual qualifiers, not medical advice.
I say try it, but you might need to go at least seven days. Filinov reports needing 9 or even 11 days for healing with severe injuries or systemic stuff.
I might ask that you keep good notes and share. It’s a sensitive topic and any anecdotal reports would be of interest to the community I would think.