Once parties agree to settle, what is the limit of time to reach a settlement agreement in Georgia?

My mother-in-law was in an auto accident. The other party agreed to settle to keep it out of court. The settlement was supposed to occur months ago, but neither side seems to have any urgency in resolving the claim. Though, my mother-in-law struggles greatly financially, and could use this settlement. Not to mention all of the medical expenses she incurred from the gross negligence of the other driver. So, what is the limit of time, if any, to reach a settlement, once both parties agree to do so.