Also, find out what would happen to them if they are financially destitute because of their incompetence in handling their finances
If they were financially destitute, no matter what the reason for them being in that state, they would be able to file with the family court for financial support from their children, i.e. the OP would have to pay up (or at least his wife, but his income would be taken into account by the court when assessing how much should be paid).
Polish law isn't like US law, so giving advice about it based solely on one's knowledge of US law is not the best of ideas.