Answer: Based on your description, they may be dead if the branches are dry and brittle, discolored, and there is no green inside. Or, they may have died back partway but still be alive.
Begin at the tips of the branches and work your way closer to the trunk, trimming to see if there is any live wood. Live wood will be flexible with green under the bark. Stop trimming when you reach live wood. You can cut back quite a bit of the branches if necessary and still have a nice plant this summer.
Next, remove the dried foliage. Place them in a bright location that is cool until the weather settles outside. Then gradually acclimate them to being outdoors by setting them in early morning sun, gradually increasing to full day sun.
In mid spring you could also begin to fertilize with a general purpose water soluble fertilizer or a slow release fertilizer with an analysis of 10-10-10 plus minors, or similar. Fertilizer should only be used during the growing season, spring through fall. As they begin to grow, and the weather warms, increase your watering.
These can be difficult to overwinter indoors. They need a bright location but it should be cool (say 40 to 50 degrees) rather than hot and humid. Ideally it would also be a spot with good air circulation. You would stop fertilizing and water only as needed to keep the soil just slightly damp while they are indoors for the winter.
I'm sorry you are having trouble with your plants.
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