his decision to lie to Dr. Mengele
An internal conflict occurs when the person has to make a decision. The person weighs different possibilities and the risk associated with each one before making a decision. This is the key here. The internal conflict is something the narrator has control over and is struggling with what he/she wants to do. Wiesel's desire for more food and his fatigue are not something he can control. He is not purposefully starving himself or denying himself sleep, these are things out of his control. His love for his father is also not an internal conflict because he is not questioning or having to make a decision about this love.