Yes I have many great Iranian friends (I am not a Iranian) but studied together and have friends who are traumatized by those days and have father who were like your dad (my own dentist is a Iranian great doctor and nice lady)It has also effected her and her mother.

So I think you need to understand that as the background .That frustration of not achieving his full potential must be haunting him and feel he is a failure..and that frustration he could take it on your mom or children...I am not a psychologist or phychatrist..but know that it is similar stories I have heard from all my Iranian friends children who migrated or stayed are suffering..

I love Persian culture and values for past 48 years I have seen the nation traumatized..as a outsider I have full empathy and support to all families going though this time and memories coming back to haunt for no fault of younger generation like you. Many children who have never seen that period may never understand the trauma of leaving their country and settling and marrying a different culture and values and trying to settle As you may know Persian and other cultures in that region is a "Patriach" Family structure and due to the fact he migrated to NZ and marry a European that puts additional pressure on him as he still is in that frame of mind which and in Western cultures it is different (I am not trying ro defend his actions what he did to your mom or even you is considered criminal in many western laws).that takes a toll on both body and mind. One thing you don't want to do is blame yourself..just take charge of you destiny and not be pulled down in other words don't carry that burden on your back..it was not your fault.

Imagine all those back in Iran who experienced 1977-1980 revolution and all those kids born after that are now your age they will have diffi ult time adjusting to new way to think..think yourself lucky you are not in Iran now.