Mil doesn’t like my child

I have two kids with my husband, we recently moved from Texas to MI temporarily, to be closer to his mom and help her bury her husband. The problem is she has made it clear she dis like my second son. He is 5 she says he doesn’t look like her son or act like her other grandson. She got my other child ice cream and toys and said she didn’t get my other son anything as she don’t approve of him. I told my husband I can’t or won’t tolerate this because she is making my son feel a certain way. I told my husband my two boys and i are going back to Texas because of her behavior. He agreed we should all go as a family and leave her to figure out her shit. As we are packing up to leave his brother start saying that she don’t have like both kids and we are over reacting and that she should be able to enjoy one grandchild and without feeling like she has to like the other. Is there anyone else that have a MIL or family member that only like one of your child and treat the other wrong? My kids are 5, and 7. My 5 yr old is a typical kid sweet, adventurous, gets into kid shit, but is very respectful to everyone and looks up to his big brother.