I am not a legal expert, and laws related to wills and inheritance can vary significantly depending on the jurisdiction. Additionally, laws can change over time, so it's essential to consult with a qualified attorney or legal expert in your specific area to get accurate and up-to-date information. However, I can provide some general information about this topic.
In many jurisdictions, grandchildren typically do not have any direct rights over the wills of their grandparents while both sets of grandparents are alive. In most cases, the beneficiaries of a will are the immediate family members (spouse, children) or other individuals specifically named in the will.
When both parents of the grandchildren are deceased, the grandchildren might inherit from their parents' estate according to the laws of intestacy (if no valid will exists) or according to the terms of the parents' wills. Once the grandchildren inherit assets from their parents, those assets become part of their own estate, and they can include them in their will to pass them on to their own chosen beneficiaries when they pass away.
If a grandparent wants to include their grandchildren in their will, they can do so by explicitly naming them as beneficiaries. It's crucial to work with a qualified attorney to create a comprehensive and legally valid will that aligns with the individual's wishes and the laws of their jurisdiction.
Remember, inheritance laws can be complex, and the specifics can vary based on factors such as the jurisdiction, the existence of a valid will, the type of assets involved, and other relevant circumstances. It's always wise to seek legal advice to understand the specific rights and options available in a particular situation.