Q: My dad wants to give his house to my sister before he dies. Will this effect his estate after death?

A: if your dad wants to give his house to your sister he may do so by deed now. He should however meet with an estate planning attorney since the gift of the house may change his mind about sharing the rest of his estate equally among the 7 children (since your sister would then get the house + 1/7 of the remaining estate.

A: If he wants the other six children to be compensated for what would have been their shares of th equity in the house, he will need to redo his Will.

A: Transferring assets during lifetime can result in some adverse tax results. When a person dies they get a step up in basis the date of death. What that means is that when the estate or beneficiary who receives the asset dies they minimize the capital gain tax they would normally have to pay. But if a person receives the property during lifetime the recipient must use the basis that the person making the gift had in the property. If the person has held the property for a long time that basis may be way below market value. For a more detailed discussion please read my article that covers this area called The Biggest (Tax) Loser: Misguided Gifts of Real Estate By Uninformed Do It Yourselfers,

Realtors & Attorneys at https://sjfpc.com/2014/01/10/the-biggest-tax-loser-misguided-gifts-of-real-estate-by-uninformed-do-it-yourselfers-realtors-attorneys/

To you other question, if he makes a completed gift to your sister, then it becomes hers entirely. His will cannot speak to that asset because it was no longer his asset after he gifted it to her.

He really needs to get with an estate planning attorney before he makes mistakes that really complicate his beneficiaries life.