I apologize for the length of this post. The last paragraph is the most important so feel free to skip to that. The paragraphs before are a very brief history of what I have been dealing with.

At the end of August 2012 my mother told me my dad and her were separating, which I sensed happening for a while. A week after this terrible news, my parents told my brother (21), sister (14), and I (24) that my dad was going to rehab across the country for a month and a half. We knew it was partially for depression and slight drug abuse, and mostly for their marriage. It was during this time that she seemingly became a new person. She told us our father was gay (which he definitely is not) and started going on dates when my dad was away and told me that they both would start seeing other people. My dad had already bought her a new house on the beach to allow her space. At first when he returned home he seemed happier and healthier, but it changed once he saw her 'new' personality.

They finalized the divorce this January, which was very difficult for my brother, sister, and me since our parents kept telling us it was going to work out. Since then, my mother has seen 2 guys on and off. Anytime I would see her, which was almost every day, she would openly talk about the new guy, what my dad to her, and stopped asking how we were doing. She started going out to bars almost every night and developed a younger crowd of friends. She decided to invite one of the new boyfriend and his kids to Easter dinner even after I expressed that I was not comfortable with it. She constantly complains about how my dad is going to put her on the streets and gives her no money, which is a lie. My dad pays for all her bills, mortgage, and car (except the gas). My brother and I try to help her understand how to save money since she tells us she is in debt even though she just built an expensive new patio and goes shopping weekly. We also try to explain why our little sister is uncomfortable at her house because every time she is there our mother has her 'new' friends (that are about my age- late 20's) or her new boyfriend. Every time we try to talk to her she gets very upset and says everyone is against her.

I am not sure how to handle this situation anymore. My siblings and I want to keep a good relationship with her, but her irrational and rude responses to us make it difficult. Any advice would be much appreciated!