How do you come about that?

What do you mean how do I come about that

Like how do you propose he didn't die?

From what I interpret it seemed as though you asked why if Snape didn't die? Why of he was alive.

But after rereading it seems that you were asking about how things would have been if he didn't die.

That is why I asked how do you come about it.

I am saying what if he didn’t die like what if Voldemort didn’t kill him

Well I don't think much would change TBH.

He would still be the professor for Dark arts and still continue teaching at Hogwarts.

Although he would have earned a lot more respect.

Okay

I agree with @Reverb frost

Harry will say thank you and more respect to him

I’d commit sucide

Hog warts would be called as snape warts