You thought before looking at Regulus again. He would adamantly deny it but he had a kinder heart than people realized. Regulus had learned from an early age to put up a cold and emotionless front to stay alive but that didn’t stop the feelings going on "behind the mask." You knew that if the two of you didn’t take the baby, Regulus would regret it later. It may not be tomorrow or the next day. It could even be years down the road but Regulus would regret turning away his own blood. You wouldn't let that happen.