a lot of this depends on the state you lived in when the debt was accrued and the state you live in now. federal debts ( like taxes) are a different matter. for all these matters i'd try finding a tax attorney that does some pro-bono work. most cities have law clinics or the equivalent, where they can help you, or direct you to someone that'll help. hope this helps you.
All of your debts and assets (bank account, house, etc.) pass to your estate when you die. The assets are used to pay the debts and if anything is left it is distributed to your heirs, either according to your will or according to law if you left no will. Debts are paid in a particular order- taxes first, then secured debt (like a mortgage) then others.