Problems With Dwarf Alberta Spruce
There are a few things that can cause damage such as this to a dwarf Alberta spruce. Spruce spider mites cause areas to first brown and then die. The problem often spreads and can kill a plant. Secondly, winter damage from wind or salt exposure can make a DAS bare on one side as well. Thirdly, any plant that might have been hit with herbicide, salt, household cleaning products, hot water from a sun heated hose etc will experience dieback.
Your plant will likely not regrow needles in the damaged areas. Check for webbing (mites), and look at your other plant, are they damaged on the same side of the tree? If this is the case and there is no webbing it is probably winter damage or environmental damage of some sort. They will unfortunately remain disfigured.