Clark had just discovered a major secret from his investigation. His sister who he thought was brain dead, was actually not. There were some manipulation in her hospital records. Yes, she received massive brain shock when the bullet was lodged in her head, but the surgery was successful. If treated properly at that time, she would be in the university by now.
Clark was so confused and irritated. Worse, he doesn't even know the hospital he's sister is admitted in. All he knows is what his grandfather told him. To think of it, he doesn't really know anything. Anything and everything he knows and think is true, are all words from his grandfather.
He wanted to talk to someone, but he had no one to talk to. Skylar definitely wasn't an option. But there was one person who was willing to be his friend.