When you find Hawk he will be in pain and ask for a medkit. First you must get the key to the large green chest by the helicopter. It is partially buried in the sand under your journal. Unlock the chest. Then put the peroxide, bandages, and tape into the medkit to assemble it. Then give it to Hawk. He will then ask for water. Look inside the helicopter for the canteen (Hidden Object scene). Then backtrack to the canyon where you start to the small pond to fill the canteen. Return to Hawk and give it to him.