Teenager using Melting Furnace 2700F

Hi, my 14 year old son ordered, with my permission, 6kg propane smelting furnace kit Melting Furnace Stainless Steel 2700°F. Looking at this I am now worried that he is too young to handle this equipment. Is this safe? When I question the safety and tell him that this worries me, he gets very upset. He wants to do this smelting in the garden. There is no one else to do it with him and I haven't got a clue what he is doing. Shall I let him get on with this?? What are you thoughts?