So my mom is asking me for the second holiday season in a row, if I can watch my 14 year old brother…

So my mom is asking me for the second holiday season in a row, if I can watch my 14 year old brother while she goes on vacation with her boyfriend. Now don't get me wrong. I love my mom. But I feel this is unfair, and wrong on her part. She left last year during the holidays for almost 4 weeks. & I kept my brother the whole time. Feeding a teenage boy is no easy task to add. Well this time, she's asking me to watch him for 2 weeks while she goes sees family in Mexico. & my husband has extrictly said no. Bc she thinks it's right to travel without him just bc her boyfriend is asking her not to bring him. Let alone he stayed with us this whole weekend. She was suppose to pick him up but didn't until Sunday afternoon. My husband is the only income we have and she never offers to give any money for him. I'm seriously sticking my ground this time. Plus he wants to go and see all of our cousins. I feel this is so unfair.