Start with the records concerning the underlying event, such as accident reports, official documents, photographs, witness accounts and medical reports concerning the injured or deceased person. For the relative’s own claim, keep findings, diagnoses, medical letters, treatment confirmations, medication records and proof of necessary expenses.
The relationship may also require evidence. A shared address, messages, calendars, care arrangements and accounts from people close to the family can show actual closeness and the shared life context. A statement of formal kinship does not always answer this question.
Section 1489 ABGB generally links limitation to knowledge of the damage and the person responsible. With psychological consequences, it may be unclear when an illness requiring treatment and its connection with the event became recognisable. Keep a timeline of findings, discussions, demands and responses. The guidance on evidence, negotiation and limitation helps structure this material.