Maybe I am biased because DT is my favourite band, but I get what he is saying.
He had a gig to play, felt like sh*t, didn't want to disappoint fans, had the ambulance run out of petrol on the way to the hospital, and proceeded to then wait indefinitely with no info given.
No, he shouldn't have complained on FB about it, but that's what he does. He is a man of loud opinions shall we say. I probably would have done the same thing but the difference is I am not a famous drummer with over a million followers.
I do live in the UK but I don't have much experience with the NHS. I get that it was their standard procedure and waiting was inevitable, but he seemed more pissed about the lack of communication. I'm sure if they had told him straight up "We can't see you until tomorrow because we have 50 cancer patients to get through" he wouldn't have been half as pissed.