Is It Legal to Get a Will Changed If the Person Has Alzheimer’s and Dementia?

No. You have to be legally competent to execute a will. Even a guardian or conservator cannot create a will. However, they can create a trust that can substitute for a will. To do so, someone will have to be appointed and then seek court approval for the new estate plan. You might also be able to challenge the new will if you believe the grandmother was not competent or under undue influence at the time she executed the new will.