He gets to remain in good physical condition for about a week, after which he goes through two weeks of captivity and abuse, including beatings, poor nutrition, injury, and hard physical exertion, mostly at high altitudes. This is followed by a stay in hospital being treated for the early stages of septicemia.
How much new hair growth is he likely to have by the end of all this jollification? The new hair growth will show as light coloured roots against the darker dyed hair. I have a so far unsubstantiated recollection that hair grows more slowly, or not at all, when the body is under physical duress
The amount of beard growth isn't a concern, for irrelevant reasons.
Googled various permutations on 'adult male hair growth' and found a lot of websites with details on male pattern baldness, some information on hair growth in adult males that didn't differentiate between facial hair and scalp hair, one site with details on how fast cat hair grows (*!*), and nothing on the impact of physical debilitation on hair growth.
Any help will be deeply appreciated.