Don't throw it out yet! The big ones are hard to move any time of year, and spring is the hardest. It sounds like a lot of roots were lost, which is why the wood is still green but the plant is unable to service the leaves. A camellia is pretty thrifty, and can survive awhile that way, but unless it develops some new roots, it will continue to decline. With camellias that is a slow process as camellias are slow growers. I would suggest using liquid root stimulator periodically and keep the plant well watered all summer, water it deeply every few days, and don't let it dry out. Also mist the leaves as often as you can to help them stay alive while the roots regenerate. You won't know for awhile if it will make it, but as long as the wood is green, it is still viable. Hang in there. A mature camellia is well worth trying to save.

If the leaves are brown, it's because over-feeding or watering during the sun is shinig on the leaves.

Watering is essential, but not too much.

Be patient and wait.

It is better to build a temporary shelter to keep the plant in over 80% shade. It should not be in full sun even for short hours.
The plant should be under intensive care. Very fine mist the branches twice daily, but not too much water.

Hopely, new leave buds will be merging later.