do i have any rights?

First of all, a POA's agency is revoked upon the death of the principal. Therefore, your sister no longer has legal standing under the POA document. That having been said, she may have been appointed your mother's executor in which case she would have a say over how the assets of the estate are handled. Among other things, while she could live in your mother's house with her son. However, she should be tryng to maximize estate assets so living there without paying rent may be a breach of her fiucuairy duty as executor. If she's not the executor, then she has no legal right to live or let anyone else live in the house. At this point you need to see a copy of the Will. If you were named as a beneficiary in the Will, you should be notified of this by the executor. Also, once it is entered into probate it becomes a matter of public record which means that you (or any one else for that matter), can obtain a copy from the probate court. Finally, even if it has not yet been filed, you can still get a copy since as your mother's child you are an "interested party" in her estate. That is you stand to inherit if she died "intestate" (i.e. without a Will). Consequently, you have a right to ask to see the Will in order to make sure that it in fact actually exists. That having been said, you could have also been disinherited but at least you will know for sure. At this point, you can consult directly with a local probate attorney who can best advise you further.