Father in law died but had no will.

I'm hoping someone can help.

My FIL died but didn't have a will. My husband and SIL are the only family left( mil passed years ago).

FIL had a house through USDA, all that's left to pay it off is $12k.

Can my husband pay it off in his father's name without transferring it into either his or SIL name? If so what would happen to the house after? Would it stay in the family so long as the taxes are paid or would the government seize it because FIL is dead?

I ask because we have $12k to pay it off (life insurance money), but we have no extra so getting a lawyer and getting things transferred over isn't an option because we don't have the credit to take out a loan and pay off whatever would be left.

(We live in AL btw)