I cant really answer this as still dealing with coffee addicted friend who ended up in hospital for a month after drinking 20 cups of coffee a day according to her husband. Shes taken to vaping instead.
Without coffee shes just going to have to confront her demons and tell them to get out I guess.
That much caffeine leads to adrenal fatigue.
Second big problem will be malnutrition. You know that coffee has some minerals, but is also a diuretic.
A long habit of excessive coffee consumption causes mineral and vitamin loss.
If I had a friend in the hospital, I would seek a good nutritionist that would work with her when she's out of that prison. If it's a typical hospital, the institutional food will cause more problems than help. The Drs and dietician will look at nutrition as an enemy that must be feared. That's the typical mindset of the industry.
I'll pray for your friend that she gets back home soon and finds the help she needs.