What should a brother working on his deceased brother's land do after finding ancient gold estimated at $100,000, while another brother witnessed this gold, taking into account that the children of the landowner are unaware of the matter?

If the discovered gold is from the Islamic eras, it is considered a lost item (Luqata), and its description must be announced for a year. If its owner does not appear, it belongs to the finder. If it is from pre-Islamic eras, it is considered a buried treasure (Rikaz), and the majority of scholars hold that it belongs to the owner of the land. Therefore, the landowners must be informed. If they claim it, it is theirs, and they must pay one-fifth (khums) of it, and the finder is entitled to a fee for its extraction. If they dispute, the matter should be referred to the Sharia judiciary.