Problem please advice

I have a problem. So I recently gave birth to my second baby. He is a boy and I have a soon to be 2 year old. My in laws were in love with my baby girl and always have her attention but since my baby boy arrived they have ignored her tremendously to the point where I am super angry. My little girl has resented she doesn’t cry but she is staring to ignore them as well. I tell my husband that if they continue like that we will have problems. They are very nice people and I know they love my kids but my little girl needs attention too. Please someone that has gone through something similar. My baby had been really good with her new baby brother I don’t want her to feel like they don’t love her