When you make and agreement with family members by word of mouth, is this legally bidding?

In laws told daugther in law to let her house go that she was paying for and that she had a house to pay for that they had purchase in the in laws name for her family to include their son! Seeing that these were family members the daugther in law did not think that asking for this in writing would be showing good faith in the in laws word. Now that they have a wild hair up their BUTT, the want to kick us out. What legal rights do we have?