He could sense something with his son, a regret perhaps, something that was matched in himself, though he was sure the wards told Draco less than they did him about the state of mind of the other person in the room.
Still he knew the regret - knew the wish to talk of what was really important. But he knew his son was not to be trusted, as much as that pained him. And so he kept the smile on his face.
'A nice Malfoy, how will the world survive from the shock?' he chuckled, before moving on. 'Speaking of your mother, is she at home or should I seek her another night?' Of course he knew the answer already, felt her as he knew she felt him. Still it was best not to show Draco just how deep that bond went.