Law / How can I find out if my parents still hold their Polish Citizenship? [4]

Hi Looker, all joined now ;)
Thanks for the application but I already have filled this out. All I really need now is to find out if my father still holds his Polish Citizenship which I'm unable to directly find out from him. Is there a way for me to find this out so I can complete my Polish Citizenship Application? Do you think its unwise to write that these details about my father are unknown on my application (in the father's memoir part)?