Thank you for your question
My name is Clare
I shall do my best to help you but I need some further informtaion first
Did your father and step mother own the house together?
Then I am afraid that no there is no claim that you and your brother can make on the house.
When your father died it passed to his widow and she is free to do with it whatever she wishes.
I am sorry to give such bad news - please ask if you need further details
You are most welcome