Parallelism between Oscar and Beli

Oscar and Beli seem to have similar experiences in life.  Beli survives her one encounter with death when the Elvises beat her up.  Then she dies from cancer years later.  Oscar survives when he tries to commit suicide.  Then, he survives when Ybon's boyfriend's thugs take Oscar to the canefield and beat him up.  Oscar does not survive the second time he is taken to the canefields.  The mongoose and the canefields are important in these life and death situations.  Oscar and Beli also like to be in relationships with liars who secretly have a wife or boyfriend in high positions.  Beli is taken to the canefields by the Elvises and beaten nearly to death; she would have laid over and died if the mongoose had not appeared and told her "You have to rise now or you'll never have the son or the daughter" (149).  When Oscar goes to kill himself he sees "the Golden Mongoose" (190).  When Oscar is beat up by Ybon's boyfriend's thugs "he felt like he was falling again, falling straight for Route 18, and there was nothing he could do, nothing at all, to stop it" (299) Why didn't the Mongoose appear then?  As Oscar is being driven to his murder he sees a bus stop and he imagined "he saw his whole family getting on a guagua, even his poor dead abuelo and his poor dead abuela, and who is driving the bus but the Mongoose" (320).  Oscar and Beli both seem to be very unlucky people and what is the purpose of Oscar being born when he lives a horrible life and then is murdered? I feel really sad for Oscar.