Can a co-signer or co-borrower increase qualified home loan purchase amount?

I am approved for 300k FHA loan, but I was wondering if I have my sibling who will be occupying the home with me, co-sign or co-borrow on the loan application, if that would increase our approved loan amount? Ideally I want to purchase a home between 400-450k. My sibling currently makes 70k annually, I am not sure if that is substantial enough? Thank you in advance for the answers.

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