As you may have seen in similar questions on the forum, this is a frequent topic of conversation:
polish-citizenship-eligibility-through-polish-ancestry-t18234.html
polish-citizenship-confirmation-t17851-260.html

I am afraid the best info I could give is to refer to the guide on Poland which offers helpful information and links to Polish government resources concerning visas & citizenship, but I would also recommend contacting those forum members who have been active within the topic for advice. You may also try contacting expats through the network (once you've made a few posts to prevent spam).

Absolutely best of luck and please share what you find as it is obviously a difficult task and the information you find can be helpful to others.

 

Have you done the obvious and requested them through the consulate?

If they were born in Poland, the documents should still exist. The cost is more expensive than doing it on your own (which would just be the actual fee), but it requires no knowledge of the Polish language.

n.b. When I inquired about the service, it was not recommended to me because the documents I needs were more than 100 years old.

 

Thanks for sharing your experience hey_now! It's great to get some perspective & tips from someone who has been through the process.