my mother had power of attorney over my grandmother's will. my aunt took power of attorney after my grandmother was diagnosed with dementia.

It's not clear whether your grandmother is still living or not. If she is, then her Will doesn't have any effect yet. If she isn't, then the only question is whether your aunt has the power to actually sell the house, and whether she is using the proceeds appropriately for your grandmother's benefit. If you really want to know whether you have a case or if anything can or should be done, the fastest way to get an answer will be for you to consult an estate and trust litigator (I am not one, but they are out there). The attorney should be able to ask you all of the questions to get a better idea of what is actually going on. If you have copies of any documents, you should show them to the attorney. This is not the type of forum which really lends itself to a specific answer regarding what can be done in a particular situation, which is what your question is asking. Many attorneys give either a free or low-cost consultation. But find one with a lot of experience who focuses on fiduciary litigation. There may be steps you can or should be taking to protect yourself or your grandmother, but if there are you'll need to move very quickly. Submitting answers in this kind of forum and then waiting for answers isn't going to be in your (or her) best interest if abuse really is going on. Best wishes to you.