Do not worry, it seems that your husband is still a student, the

is some organization in University help student in this kind of situation. But remember the following:
You mother-in-law is your mother-in-law, it would not have effect to you. But be honest, pay as much as you could;
Fill carefully the forms you may be provided by the hospital or some assistant program. This would help the hospital get the money from the government or other resource. They would be still happy, and so are you.