Is expiation obligatory for someone who contracted for a phone line and a free phone with a monthly subscription, then left the country and was unable to pay the subscriptions or return the phone, knowing that the phone was free and the line was not used?

If your brother contracted with a telecommunications company for a line at a known price for a specified period and then traveled, travel is not an excuse to terminate the contract. He is obligated to pay the remaining fees, even if he does not benefit from the service, as long as the company is ready to provide it. As for the phone, he has the right to dispose of it because it is free, and he is obligated to pay its agreed-upon price.