Hi Fainting/ unconsciousness could be caused due to many reasons, like skipping meals which can cause low blood sugar levels, low blood pressure, excessive heat exposure, excessive bleeding due to any cause, space occupying lesion in the brain, trauma, pathology in the ear. In most of these instances, oxygenation to the brain will be reduced, which will cause unconsciousness. In the scenario you have mentioned, your friend must have had some amount of bleeding leading to low pressure and faintness also with low blood sugar causing unconsciousness.Keeping head low, foot raise can avoid losing consciousness in such cases. Hope I have answered your query Dr Jyothi BL