Lease obligation upon tentants death

Sorry about your mom.  However, that is an interesting question.  I do not know if there is Massachusetts law on this issue, and I do not know the answer to your question.  However, in general, when a person dies, his estate is bound by the terms of any contracts he entered, unless it is a contract for personal services.  In that case, the death terminates the contract, because the deceased, obviously, cannot perform.  In the case of a lease, I would guess that the estate is bound by the terms of the contract.  In reality, in most cases, the estate will need time to remove the belongings of the deceased.  Until that is accomplished, the deceased is, in effect, still occupying the premises.  After that, if the estate wants to get out of the lease, under Massachusetts law, the landlord is obligated to make good faith efforts to find a new tenant.

Applying all that to your situation, I would guess that the landlord is entitled to rent payments until the lease ends or until, after making good faith efforts, he locates a new tenant.  Fortunately, the landlord in your situation does not appear to have any interest in pursuing the estate for unpaid rent.  As for the deposit, I would say the landlord is entitled to apply that to the unpaid rent.