My son as been in a induced coma due to a head injury he has his eyes open moving his eyes around but can't focus or speak how long before he wakes?

Ask his doctors: It is just not possible for someone who doesn't know the intimate details of the injury and his response to treatment to answer this question. Guidelines exist to provide prognostic information in traumatic head injuries and his doctors can use such tools to give you some idea of what to expect and what hopes are reasonable. Young people often do remarkably well but each case is unique.