Legal Question in Wills and Trusts in Missouri

Your question is not clear. First, what instrument or procedure placed you "in charge of her estate"? If there was a will, it must have been probated by you do to this. If a trust, you must be the named successor trustee. Secondly, I think you are saying that yur sister received somehow a house worth $30,000 with a $28,000 mortgage. If this is correct, your sister will have to pay or refinance the debt, or ultimately the house will be sold at a foreclosure sale. Frankly, with $2,000 in equity, after any expenses of sale, etc. there will likely be nothing left.