Is he breaking open the injectors to get multiple shots from each? That still won't cover 5-6 attacks per day, but properly set up oxygen will deal with many/most/all of those, so the Trex is just needed for breakthrough attacks. https://clusterbusters.org/forums/topic/2446-extending-imitrex/ Or vials and syringes, as Pebbles' mentioned.
Verapamil is a good example of what I was saying . . . One form (immediate release) works better than another (extended release), but most doctors don't know that. And the typical dosage required to prevent attacks is often far higher than most doctors prescribe. So it is concluded in many cases, "Verapamil doesn't work for me," when in fact it never got a test with a real possibility of working. Same for prednisone. We see person after person here who gets doses too low (such as the standard "dose pack"), and/or time periods too short, in contrast to what is known to be needed for prednisone to work for CH.
I'm with Pebbles' and your husband that these aren't great options in any event; I was just saying that many, or even most, people with CH haver not had proper prescribing, so they don't know whether they work for them or not. Properly prescribed, they usually do.