I do explain this, again in a future chapter.
Tarquin, Oliver and Orel each have a third of the trust stipend that is paid out to them from the principal which is locked.
Orel has never touched his income, it was managed almost exculsively by Tarquin. Oliver's share is used for the household budget as he, like wise, doesn't spend it, but ensures the house funds. Tarquin's share is leveraged to the hilt. He depends on Orel's money to float him and keep him liquid.
He is invoicing the town budget, and the Heritage fund (UNESCO) money for his "Projects" which he justifies expenditure for and extorts Oliver to sign by using Orel for leverage.
Oliver is just as tied to this embezzlement, and he knows it. But trapped into the cycle. Tarquin pins Orel - > Orel pins Oliver -> Oliver pins Tarquin and so on in a cycle of misery. So, control Orel, control the money, both the Stipend and the Heritage Fund.
Except now Orel's found Finn... and things are about to change.