Do you think it is wrong that my cousin who is 45 never calls her mom because her mom left her father?

she was 12 and she stayed with him. Her dad was abusive but the mom who barely knew him was forced to marry him by a woman she later found out was not even her mom, but someone who stole her to get money from a man. Her mom was beaten in her sleep one morning by her father and she decided to leave because she wanted to kill him. My cousin only calls her mom to get money and if the mom does not give it to her, she won’t call her or answer the phone. My cousin lost custody of her own kid who has a nearly perfect father. The mom says it's okay because she feels the daughter hates her. I think it is wrong to use her mom this way? Her mom admits she never wanted children by this man, but he forced himself on her – she tried to be a good mother at only 16 but could not take the beatings. How to I convince my cousin to let go of her pain and anger? Her dad was a functional addict who lost a law enforcement job selling drugs! (my uncle sucked)