Nope. It's awful to call people awful for being honest and straightforward. But that's all you've got, no actual discussion, just nasty name calling.
OP did NOT KNOW she had a cancer diagnosis. Her husband has been running around after regularly, this is indeed a regular occurrence, as caregivers have to, going to the hospital and being with her there. Caregiving a sick person is very time consuming and tiring, so I am glad she has had his support.
The only thing that was different was her daughter called an ambulance this time.
He had no idea at it was not simply another health event because he was busy parenting his child.
And he went to the hospital when he could, based on what he knew.
Whether OP likes it or not he is worried about fucking up contact with his child - and yes, this matters just as much as she does.
So, no, there is nothing awful about pointing these facts out, it's helpful. Because she could really destroy things for herself if she keeps demanding he choose her over access to his daughter.
People who have diseases, people who are sick, aren't suddenly in charge of how everyone else feels, their priorities or rights. They do not suddenly trump every other decision you have to make in life, or your right to parent your child.
He was given a choice to possibly really mess up contact with his daughter - something he is terrified of and has had to fight for for years - or delay visiting his sick wife for a few hours.
No drama llama responses are required. He waited a few hours and went to her side. That's it. It's no big deal, whether you like it or not. I can see why it feels like a big deal to the OP, but unfortunately she is not thinking clearly and you are not helping her at all.
Trying to force a parent to choose the possibility of screwing up his access to his daughter (something he absolutely believes even if OP is dismissive of it) and reaming him out on social media for taking a few hours to get to you, refusing to talk to him, refusing to even try to understand that you cannot simply command people to drop important priorities so you can have them there a few hours earlier - now that really is awful.
I wish OP the best in her treatment. She's going to need her husband, hopefully she won't try to make him choose her over access to his daughter, unless it's actually necessary. Because this time, it wasn't.