I have experienced this with many different astrological signs, but specifically with a couple of Scorps. One was my abusive ex-Scorp that I was always paying his way and looking after him like he was my son. He wanted money not only from me, but other people as well. When the money stoped coming from me to him and this lady I know, they became very cold and very ungrateful and I was treated like an enemy.
If we think logically about this situation though, my ex also had deep seated psychological issues. He suffered from NPD Narcissist Personality Disorder. People with NPD have what’s called a Narcissistic Supply. Meaning they use people usually finacially. If the supply stops, that’s when the abuse and insults hurl and they treat you like you don’t exist. So could I say honestly, that all Scorpios behave this way? I can say absolutely NOT! I think it is more of a psychological issue than looking to someones astrological sign for the answer.
It may be beneficial to ask your brother how he is treated. How she behaves around him. Does she use him as well? Often people with NPD will behave differently around others for fear of being exposed of the true person they are. They are like Dr. Jekyll and Mr. Hyde. How does your other family members feel about her?
The best thing to do really, is to try not to understand her and why she is treating you this way. If she does have NPD, you will receive the cold shoulder and not an honest logical answer. Also, if she does get in a rut finacially, do not offer her any money. The same thing will happen again.
Just focus on your relationship with your brother and for no reason upset her. Like I said if she is NPD (which if she went to receive psychiatric analysis, would probably be the case) she can have what’s called a “Narcissistic Rage”. They are very scary and be very violent.
Let’s just hope I am wrong! To the Scorps out there reading this, please don’t be offended. This is not targeted at you at all.