So sorry, 'Hubby. I'm a supporter myself (my daughter). I know how terrible it is to see that suffering in someone you love. As others have said, though, it's going to get better.
Such great perspectives you have now received from two of the greats, Freud and Tony Only! I'm troubled that her attack resumed, or she had a new attack, so soon after the sumatriptan injection, and by the number of attacks she is suffering every day. I hope your neurologist will look closely at all the diagnosis options. (From what I have read you to be saying, there is no reason that she should be diagnosed yet with chronic CH -- chronic means a year of essentially uninterrupted attacks). In our experience, you get better advice and treatment from a headache center than from a standard neurologist.
I say this a lot, and I'm often wrong, but I would want to be sure that the neurologist considers hemicrania continua as a possible diagnosis. That's a condition that has many symptoms similar to CH (and similar to what your wife is experiencing), but unlike CH it is treatable with a single medication, called indomethacin.
When they gave her the O2 in the hospital, was she breathing it through a mask (or just with those tubes that go into your nose)? Mask is essential.
It's my understanding that Ouch(UK) has been quite helpful to people with CH, particularly regarding getting proper oxygen promptly. https://ouchuk.org/ I looked there for information about the Imigram/Imitrex shortage, but didn't find anything very current. I urge you to be persistent about this (while also considering the negatives about those injections that have already been mentioned). If she does go that route, be aware that the injectors can be opened so that she can give herself smaller doses, which are sufficient for most people with CH and not as damaging. https://clusterbusters.org/forums/topic/2446-extending-imitrex/ The nasal sprays do help some people, so I'm hoping it turns out to be that way for her.