That's a good idea. I'll do that.
You'd do far better to speak to a Polish lawyer.
If she owns an apartment in Poland, is it possible for her to give it to a relative or sell it without my knowledge
There is no simple answer to that question. The general rule is no she can not but it will depend on a number of things, such as: does the apartment have separate property rights or is it just a 'spoldzielcze wlasnosciowe prawo do lokalu'? Is the woman entered into the the land and mortgage register as the owner of the property? What is the marriage arrangement (they may have separate assets, joint assets etc)? Really, you need to speak to a Polish lawyer.