The bankrupt sibling's interest in the property is now property of the bankruptcy estate.  You may be able to "buy" the interest from the trustee, or the trustee may abandon the property if he/she determines that there is not equity in it.   You should determine if your sibling has filed a Chapter 7 or a Chapter 13.  Then, determine what if anything the trustee plans to do with the property.  then, hire a bankruptcy attorney if necessary to convince the judge that the property is valuable only to you and your other sibling - and does not present a value to the creditors.