Q.Japanese maple
Our beautiful tree came back this spring however only half of the branches have leaves.
Is the tree dying?

Check the branches that are bare, do they bend or snap off?
You can scratch the bark on the bare branches. Live branches should show green and healthy tissue.
Winter damage does occur with a Japanese Maple
These links have more information.
https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-scratch-test.htm
https://www.gardeningknowhow.com/ornamental/trees/japanese-maple/japanese-maple-winter-damage.htm
https://www.gardeningknowhow.com/ornamental/trees/japanese-maple/japanese-maple-care-pruning.htm