Who is The Tienappels from The Magic Mountain and what is their importance?

The Tienappels are the members of Han's family who raise him. Consul Tienappel is a widower and prosperous Hamburg businessman. He has two sons Peter and James. Consul Tienappel is a symbol of the solid normality of the "flatlands." When Hans prolongs his stay at the Berghof, his cousin James eventually visits to persuade Hans to return home, but is successfully driven off by the strange culture of the Berghof, and the changes he sees as Hans has adapted to it.