Pictures from news.. Global post shows no shoring after failure before fire dept arrived or did much. No shoring, no ladder, no shoring plan likely.
The failure is semi circular in plan view. Big blocks of soil. No back fill. all the dirt in the trench caved in, no backfill. So this is a trench toe failure with toppling, not a slope failure. These happen fast. Dead Fred had no chance. It was criminal negligence causing death by the hoe guy, and/or excavation company.