Giving up by witnesses

Dear Sir, In my 498a case, the father and brother of my Wife, who gave statements to police under CrPC161, have given up as witness in the court, their statements being unnecessary, as stated by APP to Court. Before this, the other PWs (including my wife and her mother) who appeared from my wife's side, they couldn't stand most of the questions posed to them during cross-examination and mostly replied that they don't remember the asked details. My queries are:- 1. Is it permissible in law that persons who are in blood relation and based on whose testimony the final report/challan was submitted in Court leading to institution of the case u/s 498a/406/34 against us, can these family members/persons give up from appearing in Court as witnesses? 2. Can such persons who gave up as witness in Court be compelled by respondents (us) to appear and depose? 3. Is there any law/ruling/case law by SC citing which such persons who gave up as witness in criminal case be made to appear and depose or is there any provision for penalty/fine for such persons for misleading the criminal justice machinery? 4. Is singed statement given to police under CrPC 161 holds more weight than unsigned statement? Thank you very much. Best regards, Govind