Doctor Arrested On Section 304

One of my friend's father is a doctor practicing in Digboi. He has been arrested and Section 304 has been imposed on him. he gavr medicine for dehydration to a girl and asked her parents to get her admitted, as her condition was bad. They did not admit her and the girl died. Now he is arrested, the post mortem has not come yet. 1) Does the post mortem takes 15days, as said by doctors? 2) The lawyer says it will take 15 days to file for bail. is that so? 3) can the police arrest him without any proofs? 3) what should be the next course of action as he is a diabetic.