What kind of lawyer do I need to fight a guardian to my grandmothers house and how do I find out if the guardian is the power of attorney?

Simplest way to start is to ask her for a copy of the power of attorney document she claims your grandmother. I would also confirm your request in a writing (text message or email). Presuming she gives it to you, most likely the document will identify the name of the lawyer and the law firm that prepared the document. I would then reach out to that lawyer to find out what other changes were made to her estate plan (if any). If the lawyer does not wish to speak with you or provide you with any information, you need to speak with your grandmother to find out if she understood what powers she gave her neighbor. If her understanding was different from what the neighbor said, then you might want to record that conversation with your grandmother and then go to a lawyer who specializes in estate litigation for a consultation, bring with you the power of attorney document and the recording and any other material you have as to your grandmothers lack of mental capacity understand her actions including an identification of her medicines, the name of each doctor ( all listed on her medicines and in her healthcare benefit statements). The key is whether your grandmother was / is in control of her facilities to understand her actions and the powers given to the neighbor. If she is in control of her facilities and intentionally gave those powers to her neighbor, then you have a tougher road to prove undue influence.