Is the person who asked the questioner to check on his brother responsible for what happened to him in terms of arrest and deportation, knowing that he was unaware of the prohibited activities they were engaged in?

We ask Allah to relieve your worries and ease your distress. Whoever commanded you to go to a place whose danger he knew, and concealed that from you, is sinful, because he betrayed the trust and did not offer the necessary advice. As for guaranteeing what happened to you, he is not liable, because the one who causes an act is not liable like the one who directly commits it. As stated in Ibn Nujaym's "Al-Ashbah wa'l-Nadha'ir": "If a direct perpetrator and a causal agent converge, the ruling is attributed to the direct perpetrator. Thus, there is no liability on someone who dug a well wrongfully for what was destroyed by another's throwing [something into it], nor is there liability on someone who guided a thief to another person's property, which the thief then stole."