I am assuming Tomasz's mother was in her forties. That the earlier bitterness of a failed marriage fed into the her worst fears of dying. People often avoid. And often they avoid by finding a bigger pain to camouflage the one they have no control over. Maybe being a bitch gave her some control over the pain. Maybe Tomasz did the same thing with the meaningless sex. He could control it. It hurt him but there was pleasure too. He could mask his soul. Until it was all just over.
Well done Corvus, extremely well done.