I need three examples of how the Nazis dehumanized the Jews or treated them with compassion in Night.

Well, this answer has more to do with history than with what happens in Night.  Hitler was a member of the National Socialist German Worker's Party, or the Nazi party. After being voted into power as Chancellor of Germany in 1933, the Nazis took control of the government.  In 1936, they enacted the Nuremberg Laws, which practically strips the Jews (and other undesirable groups) of their German citizenship.  In 1938, Kristallnacht, or "the Night of Broken Glass," occurred, when the Nazi soldiers vandalized Jewish homes, shops, and synagogues.  The SS originally had the Jews quartered into the ghettos, where they were crammed and isolated from the rest of the city, hoping that eventual starvation and disease would kill the Jews off.  However, they thought that the process was too slow, so instead, they were shipped off to labor camps to be worked to death.  In some countries, they were rounded up and sent to mass grave sites where they were shot and killed. The Jews would be shipped in cattle cars packed full.  In Night, Elie mentioned the burning smell of urine and the inability to move or breathe.

However, as terrible as this sounds, they again thought that the process was too slow, so Himmler came up with the Final Solution to exterminate the Jewish race. This is what most people think about - Auschwitz, Dachau, etc - the extermination camps.  Here, the SS would select who would "live" and who would die.  Usually the young children and elderly - the people who are unable to work - would immediately be sent off to be killed in the gas chambers.  The SS would lie and tell them that they are going to get deloused, so they are standing in these chambers naked. The SS watch these deaths through little windows into the shower rooms, like it's a show. They would then release carbon monoxide into the chambers. The people would realize what was going on, so they would try to break out of the shower house.  People would climb on top of each other, trample each other, claw at the walls and ceilings. If you look at the gas chambers now, you can still see the claw marks (I visited Dachau and it was the most humbling experience in my life). From here, prisoners would unload the naked bodies from the chambers and put them in the ovens in the crematorium, after taking out anything of value, such as golden teeth. They would then be burned in the ovens.   

The ones that were selected to live were dehumanized even more so.  The one thing that connects a man to his identity is his name. To be forcefully stripped of your name is to lose everything that you hold. The Nazis stripped the Jews of their names and tattooed a number onto their arms.  Both men and women had their hair shaved.  A woman is recognized as a woman for her hair. Having that shaved off takes away her womanhood. They were stripped naked in front of the soldiers, who treated them worse than animals, and deloused. From here, they were sent off to other labor camps, where they were worked to death and fed rotten food filled with worms. If you were unable to work, you would be killed. Some prisoners were also used for human experimentation, especially twins.  Some prisoners were made into other items. They were treated as expendables.

Granted, there are instances of kindness, but almost never from the soldiers themselves.