Tell your friend eat meal in time or even more meal in a day. Every meal a small portion will do. Example 1 day we eat 3-4 meal but she needed 6-7 a day. Skip alcohol, drug( ketamine, cocaine, methamphetamine,weed&etc..) & oily food (fried chicken , & etc...).
Eat more oats + manuka honey. (It's delicious & very healthy & helpful too). May God bless your friend and get well a.s.a.p. amen.