It is simple a link between previous and next quest. After you saved little brother Riley you are flying with him to Dr. Earnhardt’s to discover what happened to the others.
Search for any survivors.
You land to discover the house is up in flames. Proceed to gazebo near house until you see Dr. Earnhardt. He is wounded but, with his last breath of air, he will inform you that the jungle warriors took your friends to the temple. You are surprised by new situation and decide to go to the temple.
Get to the helicopter.
Get back to the chopper you came from. Riley will be waiting for you. It is time for the last quest.