Due to dementia so that she cannot administer my stepfather's estate when he dies. Is there anything, any legal measure, to make sure he is not successful. His hopes are that he will be appointed administrator "because he is first born" of his father's estate. (Like being first born has ANY such rights?!)
If your mother has dementia, even if she is still competent in the legal sense, wouldn't the responsibilities of administering the estate after her husband dies be highly stressful for her?
Sounds to me like both Mom and StepDad need to discuss their wills and final wishes with an attorney.