Answer: encourage him to cough, give oxygen as tolerated, and transport
Children frequently have foreign stuck in their respiratory tract. In some case, it might block the air and cause respiratory distress which could threaten their life.
The child in this is still conscious so the obstruction should be partial. Encourage the children to cough is the best option as it is not invasive than other option. Giving oxygen also help to increase oxygen content so it will be enough for the body oxygen demand.