No, never together. His abuse of them was always separate. When he would inflict punishment upon Willa, Wojtech was not allowed in the room. He would sit outside in the hall and wait for his dad to be done, hands itching from not able to do anything but listen to Willa's screeching. The sound haunts him, he never wants to hear Willa scream like that again. He hates himself for not having done anything to stop it, but there's nothing he could have done, he was just a kid. All that stopped after they were 8, once dad began ignoring Willa full-time. Since then it's just been Wojtech with whom he interacts sexually.