Kaczynski received a villa in Warsaw's most prestigious district!
Having certain relatives who were key figures in early PRL politics and the Stalinist-era judiciary (who were directly involved in prosecuting and executing opponents of the regime including well-known wartime figures) could hardly have harmed this...
The theory of Kaczyński's father being Russian and Jewish is quite widespread though in nationalist circles.
That one's been going round the web for years without proof. They apparently lived somewhere fairly close to Odessa, however I don't think any documentary proof exists to suggest they were Jewish.