Apricots can be difficult to grow and rely on to provide a crop in Maryland; if grown at all, they tend to be planted as ornamental non-fruiting varieties (like Japanese Apricot, Prunus mume), though even those are relatively rare here. Unfortunately, Apricots are vulnerable to a range of pests and diseases, and their early blooming period makes them more at-risk for frost damage, which will prevent fruiting if the buds are open during overnight frosts/freezes. We often experience such temperature swings in spring during the window of bloom or early fruit development for apricot, as our typical frost-free date can be as late as mid-May, depending on region and neighborhood microclimates.
https://extension.umd.edu/resource/growing-selecting-planting-peach-and-cherry-trees

Potential problems include infections like Brown Rot, Botryosphaeria canker, and Nectria canker; potential pests include various wood-boring insect larvae. Stressed plants tend to be more vulnerable targets for such issues, and sources of stress are usually environmental, like drought, over-watering (or poor soil drainage), or injury to the trunk from mowers or deer antler rubbing. Aside from these considerations, trees not exposed to enough direct sun (ideally, 6-8 hours or more daily in summer) won't be able to fruit well, if at all, even if the rest of the tree is healthy.

We cannot determine the exact cause of the branch dieback from the photo, but it is significant and suggests a larger problem like infection, borers, serious injury to the bark, or substantial root death. Make sure dead branches are fully removed (following the pruning guidelines in the page linked below, under "proper pruning cuts"), but it's possible the cumulative or acute damage done to the tree's health overall is already too great. There are no fungicides or other pesticides which would be useful at this point, so all you can do is to see if the tree recovers after pruning and puts out new growth. If you do not wish to treat the tree as a primarily decorative tree from this point forward, you can replace it with either a different fruiting tree or another flowering or shade tree.

https://extension.umd.edu/resource/pruning-trees

Miri