Sirius would be in a state of panic at first. But then he would quickly gather his wits. He'd likely try to find out what caused the seizure, whether it was a spell, a potion, or something else entirely. He might also call for Remus or other trusted friends for assistance, as he wouldn't want to leave Harry alone in such a vulnerable state.
Sirius would probably be very worried and immediately try to help Harry. He might use some basic healing spells he knows.
Chapter 610, "Building a House?!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Therefore, Jiang Yan became even more entitled and bossily ordered...
If you want the clearest chapter reference, go to Chapter 2. Early on, On the top floor of the Financial Building, a gathering of dark clouds...; later, the chapter leans on How dare Jiang Li hang up his phone?.
Chapter 711, "It's Actually Her", is the clearest early answer because it turns Zhang Jing's situation into a concrete plot event.
Chapter 593, "Don't Look, It's a Bad Review!", is the clearest early answer because it turns Look's situation into a concrete plot event.
Chapter 572, "Only Second in the Country", is the clearest early answer because it turns Correct's situation into a concrete plot event. Early on, Little brother, this is a competition, and I won't go easy on you.... By the end, As the fifth question appeared, his confusion deepened..
Chapter 870, "She is My Ex-Girlfriend", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter gives readers a real answer by opening on Huo Shan couldn't believe it and covered her mouth in shock.
Chapter 642, "Congratulations to Qi Tianyu, Points Increased by 10!", is the clearest early answer because it turns Round Brain's situation into a concrete plot event. Early on, We'll be the first to catch the plane, then we head straight to party!.
Chapter 786, "Working at Chen'an?!", is the clearest early answer because it turns Jiang Shixu's situation into a concrete plot event. The chapter turns that into something concrete by moving from When Jiang Li left Taiqi's office building, it was already getting...
Chapter 700, "As long as the money is in place, I am willing to do anything!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 775, "Live Stream the Day After Tomorrow!", is the clearest early answer because it turns Jiang Shixu's situation into a concrete plot event. The chapter gives readers a real answer by opening on After meeting Jiang Li, Jiang Shixu became much happier.