E.I.
Hello.
I am so sorry to hear about this unfortunate situation. It is a very difficult one. I myself growing up had aunts and uncles who favored other cousins, with gifts, etc and they do it still to my children today. Although I was able to sever ties a bit with them, I still never forgot how it felt. HORRIBLE! These are things you remember as a child.
I can tell you what my friend's mother did because her case was a bit more extreme. My friend's father died when she was a child. Her mother later remarried and becan to have more children. The first husbands family was quite wealthy. Because the gifts were so big and obvious that were coming to the eldest daughter, she finally told them, you love all of us, or none of us...this is part of my oldest daughter's family now, and you cannot keep showing special treatment. When given the choice, the grandmother chose all of them, and they all had a pretty good relationship after that.
Maybe if you gave them this choice they would see the light? I really wish you luck.
Take care~
Lee