Your husband has, at most, if any, given that your father-in-law is alive, a partial interest in the referenced property. Therefore seeking a right to residence in that property, especially when you have never lived in it, is out of question. Also, your lawyer is absolutely right about "...I cannot claim right to residence in self-acquired flat of in-laws even though my husband lives there. " That is precisely what the Batra vs. Batra Supreme Court judgement is all about. The only exception to this judgement is where the husband has transferred properties to in-laws name to subvert the wife's rights. As for brother-in-law's residential flat, it is also not possible for you to assert a right to residence there, even though it was bought from ancestral property income. First, it will be difficult for you to prove the source of monies for the purchase. Will take forever in Indian Courts to do so. Also, you never resided there with your husband as a place of permanent residence to bring it under the joint-family residence claim. Hope this helps... Again, I am not an advocate.
If your husband's advocate is smart, he will get the entire DV case thrown out on technicality. As you have always lived in your in-laws' place, that residence cannot be called a "shared household" under the definition and therefore the DV Act would not be applicable. Remember, marriage is not the essence of the DV Act. Living together in a shared household is. If you did not share a household, you were not in a "domestic relationship" and therefore there could not have been any "domestic violence." This technical issue will have to be argued cogently by your husband's advocate to negate any judgements to the contrary based upon the specific facts of your case. He would have a good chance on appeal to win, even if the trial court rejects the argument.