Hi there and
to the forums!
Your budgies are very cute
I'm sorry they're not doing well, their best chance right now will be when they see the avian vet. Please let us know when you're able to get in an appointment! I'm sure they'll feel much better after getting an accurate diagnosis.
You've received excellent advice from the previous posters with regards to caring for their condition while you wait for a vet appointment. With the heating pad, you can put it on only one side of the cage (hung on one corner or in one half of the cage, depending on how large it is/whether or not it's foldable) and that will allow Angel to move away from the heat if he gets too hot. You only need to put the heat on the lowest setting so they don't overheat.
As for soaking the millet, even though they dehusk the seed, the fact that the liquid soaks into the seed helps, but also a major part of it is that the nectar-like solution entices them to eat millet, since they may not even eat millet if they're feeling very sick. When they eat, they keep up their strength, and the Pedialyte solution helps to keep them going.
Here's what millet in it's "spray form" looks like:
Meanwhile, be sure to read through all the links provided above! They'll help expand your knowledge even more and help to keep you up to date on the best way to care for budgies
Hope to see you around and if you have any questions after reviewing the links, be sure to ask!
Please keep us posted on how your budgies are doing