Based on the description, your friend seems to be suffering from brain damage resulting into unconscious state. The exact state of brain dysfunction can be assessed by clinical examination by a neurologist
(EEG), evoked potential studies and positron emission tomography
(PET) studies. These tests can be ordered and interpreted by a neurologist. Regarding treatment, it is mainly supportive with good feeding, oxygenation, maintaining BP, prevention and treatment of bed sores, deep vein thrombosis
prevention, physiotherapy. Antiepileptic drugs can be used to control seizures.