Of course, spineless and naive Douglas is going to allow him to participate in that quest, making Dario leech off of him. He might even give him most of the rewards because of how spineless he is.
If he doesn't tell Dario to back off in the next chapter, which I assume he won't, I am giving this a 1 rating. You have a duty to protect your daughter, so you mustn't back down against a greedy asshole like Dario.