Honeytrapped

I m from gorakhpur (u.p.), this case is related to My younger brother and he is Defence personal serving in indian Army .case is that, my brother talking to a girl who belongs same town gorakhpur .they are like girlfrind -boyfriend from last 1year .one day as he is on leave then his girlfriend called him and told to meet him , he also agreed to meet her because the had met already in his previos leave . She called him at1930 In the evening and tell him to came in a garden near to her vilage .he went there . after 5to 10 Minutes he observed that two three people coming towards him before that he come out from the field and then coming people catch him and asking that why are you here in the night he can't gave satisfacotry answer that they calle at nearest police and hand him over . He told (my brother ) To police that he gone in the garden to be fresh . Police told him to stay in police station till mornig because SHO is not available .in the morning parents of that girl came on police station and made preasure on that boy to marry her otherwise we wil put a FIR against you . Those will carryon upto that day's evening and lastly parents of that girl told him to give a writen statement on stamp paper that he will mary with her in his next leave because his leave finished that and he has to report his unit . So he decided to write this on stamp paper (by the preasure of her parents and some peoples of her vilage ), they gave him one time and told him if he is not comming on leave within one month and declined for marriage they will loge a FIR against him . This is a serving personal so the parents of girl wants to marry with this girl . In the past boy has not make any promise to marry her . please give sugessions and which type case they can make .