Why do you think that Bruno's mother and sister ignore Kotler's bad quailties

Kotler plays to the women's vanity..... giving them the compliments and attention they seem to be lacking in other areas of their life. Because of this, the women warm to him immediately and don't seem to notice other more questionable actions. Combined with the actions of the other soldiers at the prison..... Kotler doesn't stand out in the category of cruelty.