There isn’t any advantage. The IRS says the sale must be an "arms length transaction", or they will tax it like it was an arms length transaction. That means they will treat it as a sale to a complete stranger regardless of who you sell to or what you agree upon.

The only way you could get a tax advantage would be to lie about the actual sales price and accept money not recorded at the time of the sale. That is illegal and you would get hefty fines from the IRS.

Like the two previous answerers have stated – the taxes are going to be paid – the Feds want their share. However, there are some closing costs that your purchaser may be able to save money on. Since it is a family member buying your home they may accept the survey from when you bought the house, they may not want to have it inspected and they if you have owned it for a while they may not even want to get a title policy if you are sure there aren’t any liens filed against the property and you had purchased one (title policy) when you bought it. I wouldn’t really recommend the buyer not buying a title policy but it can save the buyer money.