Hazel's hound will be someone for her to lean on, in so many ways. Everyone could use a friend, sometimes, but imagine being 23 years old and housebound for ten years --- never having been well enough to finish high school, go to parties and concerts, even go to the library or a park, and definitely not well enough to get a job (Well okay, she did have one paid job as a kid, before she was sick, doing what? Dog walking!)
Imagine turning 23 not being able to move away and go to college, not being able to play the musical instruments you once loved, barely being able to express yourself at all.
And then imagine not only having Severe Myalgic Encephalomyelitis, but also having been the victim of a horrible attack while still a pre-schooler, and suffering from the horrifying memories that trigger panic attacks and nightmares. Hazel often stays awake for 40 hours or more, at a stretch, because the pain is so bad it keeps her awake, only to fall asleep and have nightmares so bad they wake her, and she doesn't dare fall asleep again.
Now imagine that young woman, tormented by pain and horrors, but having a big, reliable, supportive companion dog beside her. Life looks a whole lot better, doesn't it? Especially if that dog can increase not only her comfort but also her mobility and independence.
With Severe ME and PTSD, for Hazel, a dog is not just a pet, but a necessity.