What are my chances to evict previous home owner and his family?

[Elena Pech]

Hello, I want to buy a house that is subject to a petition to partition between several siblings. One of the owners in his late sixties with his family live in a house, and won't move out. If I purchase the house (after a court approval) I have to start eviction process. I understand that eviction of previous owner is even more complicated than eviction of a tenant. How long it may take in Massachusetts? Is there a chance that I won't be able to evict this family?