My grandfather has passed away and my mom and uncle have power of attory and have his house. My cousin and her boyfiend have been staying there totally rent free and has been asked to leave so we can clean the house out and get it ready to sell. On several occasions she has said she is leaving but still hasn't. They are tearing the house up and selling things inside the house and are also on drugs. What can we do to get them out?

What state or country?

A POA is no longer of any effect after death. Has the probate court appointed you as the personal representative of your grandfather's estate?

They are given a notice to vacate and follow that up with going to court for an eviction order. If they are selling things they don't own prosecute them for theft.