This kind of isolated/scattered branch tip dieback can be quite common on Cryptomeria (the evergreen pictured), though it's hard to determine the cause. Various environmental stressors, plus a few fungal infections or pest damage, could result in dead foliage. Trim off the brown portions and continue to monitor the plant for watering needs, but no other intervention is necessary. (No pesticide is warranted or would provide any benefit.)

When Cryptomeria or other conifers turn completely brown, that indicates that either significant root damage or plant stress occurred, or that a pest or disease affected part of the main trunk, since something is interfering with water transport between the roots and branches. Physical damage, like gnawing from voles or an invasion of the wood by insect borers, or possibly an infection like root rot or Botryosphaeria could be responsible, and since symptoms can overlap and be hard to diagnose once a plant has gone fully brown, it's hard to say with certainty what happened. If the soil drained poorly, was too compacted, or a plant is over-watered, roots deprived of enough oxygen in the soil can die back, leading to either secondary issues that can kill a plant, or to plant dieback directly. If the plant that was lost was growing near brackish water or was exposed to storm surge flooding of the root zone, salt might be at least partially responsible, as Cryptomeria is only slightly salt-tolerant.

Miri