Unlawful eviction?!?!?

So help me out ladies. My sister, her husband and son, and my other sister and mother are being kicked out of the house they were living with. They were all living with my youngest sisters boyfriend in his house( he is the homeowner). There was no lease agreement. Just him verbally saying they can stay there. Which they have evidence of (address changes, kid enrolled in that local school, bank drafts for money used to pay rent and bills) just no paper agreement. Well they've just signed for a new house and get the keys for it memorial day weekend. Can the guy who owns the house legally kick them out with no sufficient notice. He told them they've got 7 days to get out and that would put them in the street until they get the keys for the other house. Any legal advice???

Please no negativity about the situation in general. I know its abnormal all around but it is the way it is and I just want legal advice so that they can have a lawful notice and hopefully avoid being homeless temporarily