In Night, how has the relationship between Elie and his father changed during their time in the concentration camps?

In the beginning of Weisel's story, he has almost no relationship with his father.  His father is a busy community leader and his duties leave little time for interaction with his son.  Elie laments this lack of connection in his earlier years, and some bitterness in his father's alienation is present as well.  As early as page 2, he recalls that his father was :   "more concerned with others than with his own family."

However, the horrors of the Camps make the pair value their relationship.  As the terrors they endure esclate, Elie has "one thought - not to lose [his father]."  When the father and son experience the New Year, the relationship has completely transformed, from one of alienation, to one of protection, to one of closeness.  The author says, as the two contemplate their future (or possible lack of future) that they had "never understood one another so clearly."