If my mother-in-law died and owes money from a care home, are we actually responsible for this?

Mother-in-law died with no will and only a small amount of money in her bank account. She did own a house with her roommate with right of survivorship. We received a bill from the care home and the ambulance service in my husband’s name along with his mothers. She had $1,000 in her bank account which I used to pay us back for the $1,000 we already gave to the care home, she still owes $6,000 and I don't have the money to pay that nor any money to pay for all of the final expenses we have already paid for. Her taxes hadn't been filed yet either do we have the right to file them to get some of the money back we have paid out for cremation and final week of care to a private care giver? I don't feel we should have to pay out even more money to get an attorney to answer these questions and get things figured out. Can we just tell them to put a lien on the roommate’s house because it was half hers when the bills were created?