I'm sad to hear he has decided to keep dragging his feet hoping he won't have to leave. I'm quite sure he has no place lined up to go yet thinking and hoping he won't have to.
I don't know where you live, and it varies from state-to-state here in the US and I'm sure is different elsewhere in the world. For my late husband and I, we had to provide his son with 30 days written notice to vacate. Jr was not on the mortgage and that written notice still had to be given and filed with the local magistrate. With that done, if Jr decided to hem and haw about leaving, then we could have the police come and escort him and his belongings from the property.