It is not so easy to deprive the heirs of the heirs of values. For this, you will have to go to court and submit a claim with confirmation materials.
You can go to court when there are the facts of the unscrupulous relationship of the heirs to the testator. The decision in almost 100% of cases will be positive if the heirs did not fulfill their duties (they did not allow proper care, did not help the financial age or disabled person, did not pay alimony) or, that even worse, it was put on his life and health under Threat. However, these facts will have to prove, as well as to prove that the testator really needed help. This behavior falls under the definition of "unworthy heir" and is a good reason to lose the inheritance.If you are not confident in your abilities, in the fact that you can go through the entire procedure correctly, it is better not to regret money and hire experienced lawyers.