If Jace had known the discomfort that had been welling up inside Alec, he would have reached out to his brother, his parabatai, and attempted to comfort him. Jace wasn't very good at it, but he held family with such high esteem that he would have had to have tried. Even if it was a weak hand on his shoulder or words that he stumbled over - he was far more versed in providing romantic language to Clary apparently than offering words of comfort - he would have tried something.
The books had been thumbed through, Jace catching the important bits and pieces with others around him filling him in. He didn't really care to spend his free time reading about his life or the events that happened after the moment he had arrived from. His thoughts were similar to Alec's; he didn't want to read what sort of things he did, what those he cared about went through, and things he had encountered when he had no say or way to stop any of it. Would all of it really happen though? That was the latest questioned theory Jace had. If they were here, would the events still happen? What would happen to the books if they were not in their own time to let the story progress?
It was probably not worth thinking over, not getting a massive headache for. Answers would come in time, and if they didn't? He was pretty comfortable in this new New York.
"Actual time never did anyone any good. Jace Wayland time is far more effective to get you from point A to point B." Jace gave a hearty laugh as nothing was ever very subtle with him. His laugh subsided and he glanced down at the jacket. Adjusting it to sit properly on his shoulders, Jace ran his hands down along the red line detailing and nodded in agreement.
"It does, doesn't it?" Jace all but physically bit his tongue as the next question of whether or not their sister had assisted in choosing the garment threatened to come tumbling out. Alec had done him a good deed with this garment, and Jace was not going to find ways to take credit away from him. He never got enough as it was.
"Where to, dear brother? What sort of trouble do you think we can find ourselves in this city that is home, but isn't?"