Nothing can be done. A will has no power or effect until the testator (person making the will) passes away. It does NOT control or limit what he can do with his property prior to dying. A will needs to really be read as saying, "IF I still own my house when I die, then...." If he didn't own the house--whether it was gifted, sold, foreclosed, etc.--then the part of the will discussing the house has no effect.