Welcome to the forums,
I'm sorry you and your budgie have gone through a stressful situation.
I gather from your description that the "free-flight" mention was actually done indoors. That term is used for outdoor flights and this isn't an activity recommended here at Talk Budgies.
Before letting your budgie out of the cage, it's best to work with him in terms of having him at the very least finger tamed, in order to facilitate the process of getting out and coming back into the cage.
As for the dried poop on your budgie's feathers, this is something that he is able to take care of by preening his feathers clean.
I hope by now your budgie is all settled and calm. While the approach used wasn't the best, when dealing with more stressful situations it's always best to try to conceal the panic from the pet bird and to try to be as calm as possible.
You can help your budgie to settle in more easily by covering the cage on 3 sides (leaving the front part uncovered) and by having some soothing music on for him on low volume. This will also be helpful to reduce the stress levels.
Be sure to check the stickies at the top of the Taming and Bonding section's main page for all the information on how to build a good bond with your budgie: Taming and Bonding - Talk Budgies Forums