What is the ruling on purchasing a plot of land from minor children (the oldest of whom is less than 13 years old), and what are the legitimate conditions for completing the sale and purchase process in this case?

It is permissible to sell an elderly woman unless she has been interdicted due to senility or similar conditions. It is valid for a discerning minor to make a purchase, but his guardian has the option to ratify or reject the sale if he did not authorize it initially. As for an undiscerning minor, his buying or selling is not valid. The situation described should be referred to the Sharia (definition) courts.