Cops Demanded To Check The House

I don't live with my parents anymore so I wasn't there to help them with this. My father was up Sunday morning getting ready for church when he heard loud banging on the door, someone saying it was the police demanding to open the door, he thought it was my husband playing a prank on him since it sounded just like him is what he told me. He opened the door and the police were at the door, one with a gun ready and another with a sledge hammer, around 3-4 cop cars securing the neighborhood. They demanded to check the house and my father worried for my sisters and mother in the house had let them in without arguing with them. After checking the rooms they then asked to take down his personal information and then mentioned being called to the address about a domestic abuse case (husband beating his wife or something). My parents don't speak English very well so he didn't know how to ask for a warrant to search or anything and just complied since he's seen many cases in which things don't go well if they don't do as the officer has told them to do. What can be done about this? I don't think that the way the law enforcement came about this was right but is there anything that can be done about it? We live in the state of Nevada if that changes anything