Compensation for "On Duty" accident in government job.

My father is working in the Department of Atomic Energy(Central Government). Last year, on 2 January 2017, when he was working in the plant(On Duty), he fell from a height of around 15 feet. Causing severe injury in his brain. He was unconscious for almost 2 months. Now he has a lot of improvement in his condition. But still he is on a wheelchair and he has lost almost half memory. We have not yet filed any police complaint against the department. So far he was on medical leave's, but now instead of joining the duty, department continue to pressurized us to taking voluntary retirement. While no compensation has been given to us from the department. Can we- 1) Should we get any compensation? And how to apply for it 2) Can we now file a police case against department to investigate the accident. 3) What can we do if we do not want to take the VRS? Apart from this, please suggest as we can do.