The essential elements which must be proven to invalidate a Will on the grounds of undue influence are as follows:
1) The Testator was subject to undue influence;
2) An opportunity existed for a person to exercise undue influence over the Testator;
3) The person with the opportunity to exercise undue influence over the Testator was disposed to exercise such influence; and
4) The Testator's Will is the product of such influence.