home copurchase default

We purchased a two-family home (in Massachusetts, to live in) with my brother-in-law and his wife. They separated and he moved out, leaving the sister-in-law. She is not on the mortgage. They have not paid any of their portion of the mortgage, taxes, or even electric bills (one meter) for over two years. We would like to remove her from the residence so that we can at least recoup some of the lost payments by renting that half of the house. Do we have any recourse? Is there anything we can do to have the brother-in-law removed from the mortgage?

[HomeGuru]

Refinance the mortgage and have the loan in your names only.

Will the brother-in-law need to sign off on the mortgage? If not, can we force the refinancing legally?

[HomeGuru]

No but he needs to sign the deed over to you guys.
If he refuses you must file partition action in court.