Can this tree be saved? Still flowers and has leaves on the external ends of the branches.
Ingham County Michigan ornamental plum
It appears that the tree may need some tlc. If you haven't pruned this tree in a while, then I would recommend that you start there. Pruning encourages growth of healthy plant tissue and new growth overall. Typically you would prune after the tree is done flowering (now), cutting out dead wood and smaller branches to re-shape the tree. Below is a link to an article which will give you more details about what to focus on when pruning.
Also, check the base of the trunk pulling away some soil to see if there are any roots that are girdled (circling) the tree trunk. If so, cut those to lessen the constriction on the tree.
Mulching the tree and making sure it has regular deep watering once a week during dry spells will encourage the new growth. And finally, you could fertilize the tree. Although this is not usually warranted, it is an option. See the article below for more information about ways to fertilize. https://www.canr.msu.edu/news/landscape_tree_and_shrub_fertilization_guide_now_available
I would then give the tree a couple of growing seasons and see if it is improving. Hope that helps.