Needs proper evaluation.
There must be some stressor why your friend is behaving like this. Needs some relaxation techniques, psychotherapy and counselling. Moreover in such cases proper ventilation and expression of whatever your friend is undergoing has to be done. Therapy takes time...depends on individual to individual from 3-6 months. Moreover a will to be better is most important from side of the patient
Next Steps
Relaxation techniques, psychotherapy, counselling, indulge in some hobbies, meditation, yoga, exercise...u can even consult a psychiatrist .