She just believed what the brother said and doesn’t account for anything that happened? ...

She really is. You would think after everything, she would at least sit and talk to him first. And can we talk about how irresponsible she is? She knows she can't handle alcohol, but she chugs it down like water, get wasted, does dumb shit, and then acts shocked the next day. So far, there are three instances where her drinking has caused major issues for her. She needs to get help.