If Herman dies...
There’s no way Arizona can actually mentally survive Herman dying. If she dies, Arizona will lose the only person she can talk to in a casual way, feeling like and equal and feeling understood. She had that with her brother, she had that with Nick and now she has it with Herman. It’s rare for her. (I don’t even think she had that with Callie - at least, not for a long time)
The only way I can imagine Calzona ever being happy again, is by them both having buddy. Just someone who’s not involved directly with the relationship, but who can listen to their small problems from within the relationship like everyone has them, so they can get rid of them instead of keeping them inside and building up the stresslevels eventually leading to another fall-out.
There is no way Arizona can survive a dead Herman, nor can she survive a relationship with Callie without a buddy.
So I hope Herman survives OR the writers finally invest in Arizona and give her an amazing storyline about grieving and finding her true self (and exploring that true self). But since that seems highly unlikely (when have they ever really explored Arizona’s side of the story?), I think her buddy should stay.