Why do you think some Jews assisted the Germans, either by policing the ghettos or by informing on their people? (pp.113 and 117) Why might Vladek send gift packages to Haskel, who betrayed his in-laws(p.118)? Would you have done the same thing?

I suppose when you and your family is threatened with extermination, taking a job to police your own people becomes an option if it can save your (and your family's) life. It is difficult for us to judge such a decision. While Haskel is a kombinacya, or "schemer", he was also in a position to help Vladek. Haskel arranges for Vladek, Anja, and Lolek to be released in exchange for valuables. He also accepts valuables for assistance in releasing Anja's parents. I think I would have done the same thing as Vladek. Simply put, you do what you must in most situations so you and your family can survive.