Now, your parent's estate can be, so if you inherit, they can come after you for the inheritance, but that's about it.
A bank can choose to write off a debt, but if you beg and plead and say, "oh, we're poor, we can't afford to pay this. You should just write it off for us." What would the response be?
So wouldn't you think the same thing applies for a country? A government generally doesn't directly die, it gets supplanted. You don't hold dirt responsible for a debt unless it's a mortgage.
Ok, so why not have a group start a separate government not under control or authority of the original. "sell" your assets and infrastructure to the "new" body. Then "dissolve" the old body down to some minimal structure?
I mean, it works for a corporation, so why not a government?
Or, if you are going to borrow money, use some sort of limited partnership. "Corporation for the repair and maintance of blah country". If the corporation is officed by a person, then when that person dies, the corporation dissolves, but there's noone to go after.
You'd have to be willing to sacrifice the long-term credit of a person, but for the longevity of a whole country. Corps can have a scapegoat, or even a martyr...