Question regarding a short sale

I have a question I was hoping someone would know the answer to. Here is the situation. We have a client that has had their house on the market since may this year. The market in this little town is SLOW! They paid 322,000 five years ago for this new five bedroom home with three and a half baths. Originally they listed it at 289,900, now they are at 249,900. They received an offer that will make it a short sale. Not by much, maybe ten thousand. The catch is the buyers want to settle in three weeks. The client has called the mortgage company to explain the situation but they don't want to hear it. They say the turn around time is about two months. The client explained to the bank that it would be a greater loss for them to turn the offer down in the long run but the bank dosent want to hear it. The question is, is there anything the homeowner can do to get the bank to work with them or is this a dead deal? The buyer needs to settle in three weeks and wont budge on the price or time line.