Harry Potter could visit Snape in the hospital. Despite their past differences, Harry might feel a sense of obligation or curiosity. He could be there to finally have an honest conversation with Snape and perhaps gain a better understanding of his actions throughout the years.
Snape might initially be shocked. He's not one to show much emotion openly, but internally he could be very disturbed. He might start investigating what happened to Hermione immediately, using his skills in potions and magic to try and find a cure or at least understand the cause.
Snape could initially be skeptical. Given their long - standing enmity, he might not believe that Harry's apology is sincere at first. He might respond with a cold glare or a sarcastic comment, like 'Potter, your apologies are as empty as your head.'
To evaluate Snape's characterization, look at how his loyalty is portrayed. In the original series, he was loyal to Dumbledore but also had a complex past with Voldemort. His relationship with students, especially those in Slytherin, should also be considered. If he's too soft or too harsh compared to the books, it might be a sign of poor characterization.
There could be other Death Eaters that Snape knew in his life. In the afterlife, they might be there to either confront him about his double - agent status or to seek redemption themselves. And sometimes, characters from Snape's childhood, like his parents or childhood friends, might appear to add more depth to his backstory and his experiences in the afterlife.
Snape might initially be taken aback. He's used to students being intimidated by him, so Hermione's outburst could shock him into momentary silence. Then he might retaliate with his usual sarcasm, trying to put her in her place.
This could be a modern AU (Alternate Universe) fanfiction where the magical setting is replaced with a contemporary one and Snape takes on a non-magical job like being a bartender.
Snape might be initially in shock. He had trusted Lily deeply, so the betrayal would hit him hard. He could become very angry and bitter, perhaps vowing revenge against her. He might also close himself off emotionally, not wanting to trust anyone again.
He could also be secretly amused. Despite his stern exterior, Snape might see a bit of his own unrequited love in their relationship. So, he might give them a stern warning but not be as severe as he usually is.
Snape's reaction could also be one of extreme caution. He would be constantly on guard, worried that Harry might discover some of his secrets or that Voldemort's supporters might target Harry while he's in his care. So he would be very vigilant, but this might also lead to some over - the - top reactions when Harry does something even slightly out of the ordinary. However, over time, this vigilance could turn into a form of care as he gets used to Harry being around.