There's also that Harry shouldn't freeze, he should transmute (as was suggested somewhere above) (or perhaps he should freeze and then transmute). Freezing is rather disastrous if it gets warm again. Even if the transmutation goes off it's relatively fine as long as he arranges it so that the transmutation can be redone quickly.
At least he is someone with something resembling medical training, which is some big potential to help, since harry wasn't even clear on how to use a first aid kit.
At first I thought that Harry just sitting there was counter-productive, but then I remembered they probably wouldn't let him kidnap muggles even for a night. However his father would be brought in promptly if Harry asked that.
Also I tried to do some fact checking while typing this, but it turns out new chapters had come out (so I'll drop this and go read them instead).
It seemed to me it was the way Harry told them off. He didn't exactly act like the day was wrapped up and everything was already said.