Answer: Transplanting is best done in late winter/very early spring or in the fall, and taking as much of the root system as possible. Then you would trim back the top growth somewhat to compensate for the roots lost in the digging. If the tree had been in place for several years or longer, it would have been advisable to do some root pruning the year ahead of the move to concentrate roots closer to the trunk as well.
Based on your description, the tree may be dead/dying due to root loss and shock. Live wood will have green just inside the bark and it will be supple. Dead wood will be brittle and discolored brown or gray, it will snap off in your hand. If the two small branches are alive and are above the graft, it may be able to releaf and then regrow once the roots become re-established in the new location.
It is not a good idea to fertilize a stressed tree. Instead, you might top dress with some good quality compost. The best thing you can do is keep the soil slightly moist like a wrung out sponge, not sopping wet/saturated and never dried out. Using several inches of organic mulch in a flat layer over the root area will help keep the soil more evenly moist. (Keep the mulch a couple of inches away from the trunk.) If you see any new growth coming from the ground or from below the graft, remove it immediately. This will keep its energy directed to the weeping top portion of the tree. After that, all you can do is wait and see.
I hope this helps.
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