my sister has this bizarre behaviour, she isolates herself when everyone is around, behaves arrogantly, she keeps on saying she doesnt want my aunty and her kids who are living with us now at home because they annoy her and are not her relatives. she's mean to my kids too and brothers as well saying they are not her relatives. she is very good academically until recently when she was dismissed from school due to drinking. my dad is so hurt about it he doesnt even speak to her any longer. they used to be very close though before the incident from school. could this be the cause? is she frustrated? some people think it could be high fever?