Problems with mother

Charlotte

So back story, I've never been close with my mom. She left when I was 5 and my dad raised both my brother and I on his own until I was about 13 when he remarried. He passed in 2011 and I've been devastated to say the least. Anyways, my mom started coming around after I had my daughter (18 days after my dad passed) but the past year, she has been acting like a spoiled brat.

She hates my brothers wife, she hates my dads widow and EVERY single time I mention spending time with either of them, she threatens to move far far away. She complained this past Christmas about having us Christmas day, so my husband and I rearranged our schedule to please her. She then has the nerve to say she never got to relax Christmas day and it was ruined. Then she goes on about how she hates her husband and wants to separate and sell the house and part ways. A week later she doesn't want to move....now I mentioned to her that we went to my nieces birthday (she doesn't consider it her grandchild because she hates my brothers wife) and she rabts about how she would never waste money on that kid, begins to go on about how her husbands son (estranged for 30 years and just recently met him for the first time) is so wonderful and nice unlike her own kids. Thanks mom. Now she is moving as far away as she can since her kids want nothing to do with her...Its my bday this week and I have had plans for this weekend for weeks. She's mad because I'm not rearranging my time for her. My husband has helped them fix their vehicle multiple times, we've spent every Mothers day, birthdays and Christmas's with her and she still treats me like this. I want to tell her like it is, tell her to stop getting offended because I have a decent relationship with my brother..basically tell her like it is but I'm scared. In the summer she told me she was better off killing herself (yes that hurt to hear) because she was bitter at everything. And I'm scared she'll say the same thing if I try to tell her how I feel. What would you guys do?