Handling a decedents debt

Dear Len & Rosie,

I have been estranged from my biological father since I was twelve years old. About six months ago he called up and said that he was dying and would like to cultivate a relationship. This man is a dead-beat. He still has a pending child support claim against him, somewhere in the neighborhood of $15,000 to $20,000. My sister and I are 24 and 27 respectively. Is there any way to protect ourselves from having to absorb his debts upon his death? I believe that he has incurred a moderate amount of credit card debit. He currently does not own any real property or have any life insurance policies. As I understand it, he was married to another woman for a number of years, however she died a few years ago due to cancer. I am not aware of any other children that he may have had. I assume that it is a possibility that he does have other children. I am also aware that he currently receives SSI due to being partially blind.

I am not trying to be insensitive to his situation, but I want to make sure that we are as financially protected as possible since we are both relatively young and just beginning our own lives with our own families.