On the other hand, he could feel ashamed. If he realizes that he has truly made a mistake, seeing his father so angry and disappointed could make him feel bad about himself. He might lower his head and not say anything, with a look of guilt on his face.
Snape might initially be taken aback. He's not used to students standing up to him so forcefully. He could glare at Hermione with his cold, dark eyes, trying to intimidate her into silence.
He might be extremely hurt and confused. Harry has always seen Sirius as a sort of father figure, so being disowned would be like a huge blow to his emotional stability. He could become withdrawn and start to question his own self - worth.
He might be initially shocked. Snape is used to students being intimidated by him, so Hermione's outburst could catch him off - guard. He may glare at her silently for a moment, trying to regain his composure.
Sirius might immediately pull Harry into a tight hug. He would be very protective and try to comfort him. He might say some soothing words like 'It's all right, Harry. I'm here for you.'
Maybe James Sirius Potter did something really reckless. For example, he might have put himself in danger while exploring some forbidden areas in Hogwarts. Harry, having gone through a lot of dangerous situations himself, would be worried and yell out of fear and frustration.
She might get angry right back. Ginny is a strong - willed character. So, if Harry yells at her unjustly, she could stand her ground and yell back, not willing to be pushed around.
In some fanfictions, Snape might see this as an opportunity for his own growth. He might accept the apology gracefully, realizing that holding onto grudges isn't helping him. This could lead to a new relationship between them, where they start to understand and respect each other, or at least tolerate each other's presence.
As time goes on, Harry could start to explore what it means to 'please' Sirius. He might recall their past relationship, the things Sirius likes and dislikes, and try to use that knowledge to his advantage. He may also feel a sense of loyalty towards Sirius that, despite the odd circumstances, makes him more accepting of the situation. For example, he might remember Sirius' love for adventure and try to engage in some magical adventures with him in a way that 'pleases' him.
Harry might be initially shocked. He could feel a mix of sadness and a sense of responsibility. After all, Sirius was like a father figure to him.
She might be shocked at first. Since Harry is yelling, which is out of character for him in many cases, Lily could be taken aback and not know how to respond immediately.