---------------------------------------------------------------------You should read "The millionaire next door" if you haven't already. There's an article about parents who favor a child and "strengthen the strong and weaken the weak"...in this case, you are the "Strong" and you are strengthened by your mom's action because you need to be more independent than your brother. Your brother will suffer once your parents are no longer able to provide for him.
I dont' know what to say about the son favoritism...it's partly why my parents said to not date Asians from certain backgrounds because the men never lift a finger.
I totally agree with cola262's two points stated above.
1. The favored and pampered son grows up not knowing how to take care of himself, while the neglected daughter learns to be independent. Therefore, what appears to be a loss is actually a blessing in disguise.
2. A a mother of two girls, I also watch out for the welfare of my girls to make sure that they do not date or marry guys from "very traditional" families in which girls are viewed/treated as second class citizens, or rather belongings of their husbands. In these "traditional families", I never see the sons do any housework. Their selfish and mindless behavior just irritates me.
Like you, for years I wonder why disadvantaged women from traditional culture treat their daughters and daughter-in-laws as unfairly as they themselves have been treated by men and elder women. I guess, as someone pointed out earlier, that they do so because it is the way they were brought up and trained (or rather programmed) to think.
Therefore, I think you should not hold any grudges against your mother no matter how unfair she is. She does not know what she had done to you. After all, she is your mother. I do not know any mothers who do not love their own flesh and blood, even if they play favoritism. Furthermore, your mother does not have too many years left to spend with you. Try to treasure the remaining time she has with you. Ignore her actions if they bother you. Just respond to all the positives.