Buying a home from family member, I'm worried about taxes?

I'm purchasing a home for 40k from my brother, who previously bought it from our father, it was appraised 3-4 years ago, when he purchased it, for 95k. I'm working with a mortgage broker who advised me to use a gift of equity for the down payment, and to have the sale price at the appraisal value of 95k, while my brother only wants the 40k, which is what he purchased it for, then he is to return the difference to me. I'm concerned about taxes, whether they be capital gains, sales tax, or gift tax, I don't want either of us to get stuck paying more than our share. We are to meet with a lawyer eventually but I want to walk in informed. Professional advice would be much appreciated.

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