Back tracking on property transfer after divorce

5 years ago

My sister got divorced couple of years back. both she and her husband are officers in Indian Army. There were two flats which they took on loan. both were on her husbands name and he pays the EMI with his salary while they used her salary for all household and other expenses. 6 months prior to divorce during settlement, they agreed (on a legal paper) that one of the flat will pass to her. it could not be transferred immediately as it was under some army scheme and need to be registered in Husbands name first upon completion and only then it could be transferred to her. he has been stalling the registration since couple of years on some excuse or other and has got it registered in his name now and refuses to transfer it to my sister. On the final papers during divorce (6 months after the settlement agreement), they mentioned that all the settlements are done (though the flat settlement was not done as it was not complete for property registration ). All the legal proceedings were done by husbands family lawyer who represented both the parties and not sure if he did it intentionally. My sister did not have any legal contacts and signed everything on good faith as didn't expected this.
Now there are 2 legal papers, one pre-divorce settlement (6 months before divorce) which says that she will get the flat. Other, final divorce paper which says that all settlement is done.
Can she file a case of cheating to get her rightful share what was agreed during pre-settlement? What are her options? Kindly advise.

Thanks,