Boruto might be in awe. He has always known his father as the Hokage, a powerful and respected figure. Seeing Naruto's past full of struggles, loneliness, and determination would make him realize how far his father has come. It could also make Boruto more empathetic towards Naruto and perhaps inspire him to be more like his father in some ways.
Well, Boruto could be very inspired. Naruto's past is full of struggles, from not having parents around to being constantly underestimated. When Boruto discovers this in the fanfiction, he might realize that his own problems are not as big as he thought. He could be motivated to work harder and not take for granted the things he has, seeing how much Naruto had to fight for everything.
The rest of his friends would probably gather around him, offering support and trying to cheer him up. They'd bring him water or whatever they thought might make him feel better. They'd also share stories to distract him from the pain, like the time they had an adventure together and overcame a difficult obstacle.
Boruto's reaction would be complex. He'd be heartbroken, for sure. He might start to question his own worth and purpose. But over time, he'd realize that he has to carry on Naruto's legacy. He'd become more serious and focused. He'd also become more empathetic towards others, understanding the weight of sacrifice. He might even start to study Naruto's techniques and leadership style more closely, trying to emulate the things that made Naruto such a great Hokage and hero.
His friends from Team 7, like Kakashi, would feel responsible for Naruto's situation. Kakashi would likely use his resources to find a proper shelter for Naruto. Shikamaru and the others might come together to form a sort of support group for Naruto. They would pool their resources, like money and food, and also try to cheer him up by sharing stories and jokes.
Boruto and his friends would face many challenges in adapting to the past. They are used to modern conveniences like instant communication devices. In the past, they'd have to rely on messengers or their own physical abilities to communicate. Also, they'd need to adjust to the different fighting styles and weapons. The ninjutsu they know might be too advanced for the past, so they'd have to be careful not to show off too much and draw unwanted attention. They might also struggle with the food and living conditions which were much more primitive compared to their time.
Sakura, being a medic - ninja, would likely be very concerned and immediately start trying to diagnose and treat Naruto. She might be constantly by his side, using her medical skills to ease his symptoms.
Sasuke, who has his own complex relationship with Naruto, would probably be in denial at first. He's seen Naruto as this strong - willed person, and the idea of him having schizophrenia would be hard to accept. But as time goes on, he would become more protective. He might train Naruto in ways to control his mind during the episodes, using his own experiences of mental discipline. As for Kakashi, he would be empathetic. He has his own traumas, and he would do his best to support Naruto, maybe sharing his own stories of dealing with difficult mental states.
There could also be friends who are so loyal to Naruto that they would consider following his request if they truly believe it's for the greater good. However, they would be deeply pained by it. Kakashi, for instance, might understand Naruto's selfless nature but would also struggle with the moral and emotional implications of taking his life.