Will not created for the property by mother

My husband and his siblings are total 7 children - 4 sons and 3 daughters. My mother in law owns a flat in Mumbai and she expired recently without a will. The flat is up for redevelopment and the costs are been borne by my husband. He has been taking care of all the maintenance and overhead costs from the time the flat was bought. She had been staying with us from the time we married - 11 years. We had been looking after her expenses medical and otherwise single handedly without help from any of the brothers or sisters( except if she had been provided money by any of them). She has not written a will but wanted my husband - her last born to own the said flat verbally. What can be done in this case?