Tax credit for the co-owner of the house?

My mom is the co-owner of the house. Her name is in the tax credit from the mortgate company. I think that's consider co-owner and not co-signer. But I know my husband is the primary owner. My husband's name and my mom's name is in the mortgage because I wasnt qualified when we But I was wondering if she will be getting the half of the tax credit of the house. She is only paying $1000 and my husband and I are paying the remaining $2400 of the mortgage payment. But she wanna get half of the tax credit. How does it work? Is she considered co-signer or co-owner?

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