He is looking distressed with that black beard. So I wouldn't treat it as brumation right now.
I highly recommend trying to do some nebulization treatments on him. That helps tremendously
when they have respiratory issues. He will need to start them immediately, can you get one from
your vet? If not, check with the local drug store to see if you can find a nebulizer. You can use
a sterile saline solution z for treatment if you don't have anymore medication.
Also, can you place him on a slight decline overnight, to help any fluids drain from his lungs,
in case some have been aspirated.
Thanks for all of the replies. I am sad to say that Toothless passed last night. He was very stiff, couldn't open his mouth, flipped him with no reaction. His eyes were very sunken in and stuck open a sliver. My daughter and I cried a bit and he will be laid to rest when we get back from Dallas on Sunday. I will likely replace him as we have the whole set up and looking at an empty cage is not fun.
Aw, I'm so sorry you lost your boy in such a traumatic way. You have all my sympathy at this sad time. Hope you can get a new scaly friend when you're ready.
Seeing my sisters dragon this past weekend, I realized that he may have never been well. Her little guy was bendy and flexible and toothless never was. He also gripped tightly with his back legs and toothless never did, even as a baby. So, I'm going to say that I'm glad we could give him the best life we could.