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.
Kurama might become angry at first. He's a powerful being and being neglected would likely wound his pride. He could start causing some minor disruptions inside Naruto, like making it harder for Naruto to access his chakra.
His friends' reactions could vary greatly. For example, Choji might be a bit scared at first, seeing Naruto as a wolf. But once he realizes it's still Naruto, he would offer him food. Ino could use her mind - transfer jutsu to communicate with Naruto in his wolf form. And Hinata would be very concerned and would stay close to Naruto, trying to protect him from any harm that might come his way because of his new form.
Sakura might be really surprised at first. She could be a bit skeptical about whether it's really Naruto or some kind of trick. But then she would probably try to help him find a way to change back.
At first, they might be a bit suspicious of each other. Boruto has heard stories about Kurama but has never really interacted with him. Kurama, on the other hand, might be cautious as Boruto is Naruto's son and not sure if he can be trusted. But as they spend more time together, they could start to respect and rely on each other.
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.