Reibun
、。

My older brother passed away suddenly two years ago, and my sister-in-law has been bravely keeping the small jewelry store he left behind going all on her own.

Literal

Older-brother [subject-が] suddenly-died [nominalizer-の] [topic-は] 2 years ago, sister-in-law [topic-は] alone older-brother [gen-の] left-behind small jewelry-store [obj-を] bravely has-protected.

A quiet, reflective sentence. 急逝 ('sudden death') is a Sino-Japanese compound — 急 ('sudden') + 逝 ('pass away'), the formal 'pass away' kanji used in obituaries. 義姉 ('sister-in-law / elder brother's wife') is a formal kinship term. 遺した is the past attributive of 遺す ('to leave behind'), specifically the 'left behind after death' kanji (distinct from 残す). 健気に ('bravely, gallantly') is a literary adverb often used for someone enduring hardship with dignity. Elevated, heartfelt narration.