@Faryshta Even if he does this goblin problem might follow him. They had to be out of options to come crawling to him for help after everything else that's happened since the start of this. If he can solve their problem and his problem with the same action, and not have to consider whether their problem might become his problem as well anyway, then why not do it?
@Glomoro
Honestly, he should have gotten a better deal. I would have at least made the guild release a public statement about how the kingdom was saved by the man the king did a great disservice to multiple times making him publicly lose face.