I've personally gone without food for nearly 45 days in an experiment in 2001. I lost a third of my bodyweight and had to spend most of my time in bed as I was very weak. I couldn't have done this without liquids though the no-food rule was very strict and even soup was not allowed.
towards the end of this peroid, I was quite delusional, and was suffering audiovisual hallucinations. Doctors overseeing me were convinced I would suffer irreversable organ damage after 45 days and I was then given drugs to stimulate my apatite seeing as my system was no longer responding to normal stimulae.
Recovery was rapid once my digestive system was re-initialized, with an intake of about 5000Kcal/day.
During the experiment, ordinary tasks became increasingly more difficult both as a cognative and physical effort. As a result of this experience, I would suggest that after 40 days, death is a very real possibility without a great deal of help, medically and physically.
It is entirely possible that this person genuinely believes he is being sustained by magick as there is a peculiar phase when the apatite is gone, but enough energy remains to feel reasonably fit and well. This period could easily be mistaken for a divine experience as it seems to defy reason. However this period does not last long, about 10 days, then starvation proper begins to set in. A positive mental atitude will significantly alter the abitlity to function, but even this cannot last beyond what becomes physically unsupportable.
The programme originally began out of suicidal ideation, but then evolved into an experiment with the influence of the medical staff. I was in a special psyke unit at the time with 24/7 medical facilities. I quit in the end due to repeated requests from family and friends. I wouldn't reccommend anybody else attempting this as it is fairly dangerous. I think 40 days would be the limit for most people, with rapidly diminishing functionality then onwards. Without energy to function / collect and process food, death would be an increasingly likely outcome.