My sister's MIL is rude to her stepgrandchildren (my sister's kids). She deliberately ignores them or blatently tells them to be quiet around her. At family gatherings she makes a point of telling everyone they are not family members. She does not buy them gifts or even send cards, but she spoils her "real' grandkids with gifts. She even called on of the stepgrandkids a 'fat a**.' My sister's husband has spoken to her but she feels justifies in her actions.