The owner of the house is not allowed to shift half of the tax liability, on any taxable gain, from him to you, without some legal reason.
A common situation is the sale of a deceased relative's property where the new owner wants to share the proceeds with other family members. Since there was no legal obligation to to so, the money transfer is considered a gift for tax purposes (not taxable to the recipient of the gift).
There is usually little or no capital gain on the sale of inherited property due to the step up in cost basis
