What to do about my mother in law showing favortism between her grandchildren?

okay, My mother in law has three sons.. the oldest son and his wife have two boys ages 5 and 7, the middle son and his wife has 2 girls ages 2 and 1 an they are expecting another baby, im married to the youngest son and we only have one daughter.. She will be 2 next month.. my mother in law shows favortism with the other two granddaughters over my daughter.. example: she had been telling me for MONTHS that she was having ALL three girls matching dresses made.. the other 2 girls got theirs but my baby was left out.. when i confronted her she said those were different dresses than the ones she is having made.. well now the other 2 girls have gotten another set of matching dresses and once again my daughter was left out.. when confronted this time she lied.. another example is with the other two girls, she paid and helped do EVERYTHING for their birthday parties.. She left before my daughters party was over.. she NEVER comes to my house to see my daughter and stays with the other 2 girls.. we all live next door to each other as well.. Also, she didnt even CALL on my daughters FIRST BIRTHDAY!!!!!! she just sent me a text!!! its rude and my husband wont stand up to her.. what can i do?? PLEASE SOMEONE HELP ME before i lose it!!!!!!!!!!