As this Freeper Pumblechook stated: it is impossible for them to even think of doing this unless you are months and months behind in paying them. And even then, they cannot put a lien on your house without a lot of written notices and lots of proof that they have attempted to collect on this debt. You have time to get help and work something out. You should do as others here have suggested, and if a lawyer cannot be found who will help you at no or minimal cost, go to your local Congressman's office and social services offices. Do that anyway, come to think of it. They will give you some advice. There are laws that hospitals must adhere to about treating people and not harassing them immediately for payment. Yes, they can certainly go after their money, but not threaten you. You need someone to help you work this out and think clearly.
In the meantime, prayers for your husband that he will recover. I am sure this is not helping him to have these worries now.