Case under Sec 306

My brother got married in year2011 to a colleague of his who was working in same office ,it was a intercaste marriage ,initially both sides were not ready later got ready and everything was working smoothly in 2014 my sis in law delivered a baby girl in month of Oct 2014 and December 2014 she came back to her inlaws house after delivery with baby. After 8 days of coming back , On 22nd December 2014 my sis in law she left house saying will go to office which is at jogeshwari near to malad so will come back within 2-3 hours, At that time baby was 2months. In evening she did not come back and later we came to know she died in train accident at vashi , late her sister , sisters husband and her mother came n started blaming my parents . My sister in law's sister she logged an FIR on 4th Jan 2015 , putting alligations on mother in law, father in law, her husband and myself saying because of mental torcher she commited suicide. when my sister in law died my brother was at delhi for official tour, and she had send her messages regarding her money distribution and said that she is commiting suicide on her own. Now since 2015 there was no inquiry from police no once came and harresed but suddenly on 30th May 2016 morning police came and took my brother, n my parents to police station, my brother is in Thane jail n we are still waiting for our Anticipatory bail , my father n mine bail rejected from Dindoshi court and now we have applied from High court, Please suggest me if we get no AB then wht shd we do?