Overall, Giyuu's ending in the manga is both satisfying and bittersweet. He achieves a certain level of closure but also leaves some room for interpretation. It depends on how you view his journey and growth throughout the story.
Sakura may react with a sense of urgency. She would drop whatever she was doing and rush to Naruto's side. She'd be worried that something truly terrible has happened. If Naruto is hesitant to talk, Sakura might just sit quietly with him, waiting for him to open up. This would show her patience and understanding, and also how much she values Naruto as a friend.
She might be initially shocked. After all, Draco is usually seen as this tough Slytherin. But then she could feel sympathy. For instance, she might offer him a handkerchief without saying much at first.
Often, Harry will offer her a handkerchief or a tissue if there is one available. He might also put his arm around her in a comforting gesture. In 'The Common Room Crisis' fanfic, he does just that and then stays with her, listening intently as she pours out her feelings. He is patient and understanding, which is in line with his character in the original books. He tries to make her laugh or at least smile by sharing a joke or a funny memory. This shows his deep friendship and care for Hermione.
Kakashi might immediately offer a comforting presence. He could put his hand on Naruto's shoulder and just be there silently, letting Naruto know he's not alone.