When unloading timber to a slinger

When unloading timber, a log fell from the wagon onto the slinger of the Gusev timber transshipment base. From a blow to the head and back, leading to injury, Gusev was cured for a long time in the hospital. At the end of inpatient treatment, the worker was declared disabled as a result of exacerbated hypertension.
Gusev demanded to give him an act of accident, but the administration of the base refused him, explaining his refusal by that. that before the accident he suffered from hypertension and that partial disability occurred precisely because of this disease, and not as a result of the injury. Assess the appropriateness of the employee’s requirements. Resolve the situation essentially with references to regulatory sources.