Certified GKH Gardening Expert
I would check to see if the remaining wood is still alive. You can do a green scratch test for this. Starting at the top, simply scrape away a small part of the bark on the bare part of the tree. If you see any green under that, it is still alive. If you do not, it is likely dead. If you only see brown, work your way down the branch until you find the green. Alternatively, you can bend the bare branches. If they are alive, they will bend easily. If they are dead, they will snap.
If the branches are dead, you need to remove them. If they are alive, give them some more time to leaf out. It was an odd winter and this may be affecting the leafing of the plant.