Is it permissible to complete the excavation of a treasure discovered in a friend's house, by means of a person who seeks help from jinn, while committing to avoid any forbidden acts, and is this money lawful?

Some scholars, such as Sheikh Al-Islam Ibn Taymiyyah, permit humans to use jinn for permissible matters, such as bringing money or repelling harm, provided no Sharia prohibition is committed, though this is rare. Most of those who use jinn are far from guidance, liars, and practice sorcery. Sheikh Ibn Uthaymeen prohibited this act because the talismans used to summon jinn are often polytheistic, and they entice those who seek them out. Therefore, they must be boycotted and avoided. As for prohibiting the use of jinn even for permissible acts, this is to block the means (sadd al-dhara'i'), for although the possibility of achieving this without prohibitions exists, it is not ruled permissible for fear that people might incline towards learning what harms them.