Alerting Poland's local land registry offices?

My father had a polish girlfriend 5 or 6 years ago that he took care of and allowed her to live in a flat that he owns in Krakow, since then my father got very sick with Cancer and then 3 years ago had a very big heart attack that caused a brain injury, he cannot make new memories and is very much like a dementia/ Alzheimer patient. The issue is this girl appeared back on the scene a year ago, my father has sent her money..she is now trying to get him to write documents that give her power of attorney or i guess ownership of his apartment in Poland.

The thing is my father is under Power of Attorney himself so has no control over these kinds of things due to his mental situation.

Is there anyway that i can alert local land registry offices to this fact ? If she were to get him to sign documents or grant power of attorney they are null and void.

You could try, and it probably isn't a bad idea. Possibly contact the local land and mortgage registry court and have your name entered into the LMR book entry for the property as holding a PoA for an incapable owner.

But anything that she would need in order to gain ownership of the flat would need to be notarised, so you don't need to worry too much.

Frankly your major concern is that a sitting tenant in Poland who doesn't want to leave is a major pain in the arse to get out of a property.

I could bore you with lots of legalese but the best advice I can give you is to get a lawyer. no way around it, just get a lawyer. having said that I wouldn't worry too much, the law generally protects the best interests of the direct descendeants in situations like this.

How can I find how much land or properties my father own

You can go to the local council to find out what property taxes he is liable for and so what he owns under that particular gmina. They may or not help you without any formal power of attorney if you explain the situation.