Altered Will

What is the name of your state (only U.S. law)? Pennsylvania My grandmother was upset at my father and had a lawyer(my fathers) draft a will cutting him out. About 6 weeks later my father drove her to the lawyers and they crossed out my name and inserted his to benefit him.She initialed in the margin. Suppossedly she never signed draft until the changes were made. Father was in room at time of signing. Is this undue influence? Would the will be void since she never signed unaltered draft?Or would they probate will without the mark-ups?Thanks