Автор (вот мои мысли)) по делу, как прагматик, я бы сделала следующее:1. Try to figure out his proper spelling ex andrey Andrei andriy and andrii могут быть одним лицом.2. Дедов адрес спокойно может быть в архивах КГБ начните там.3. You can try to find the way to search the public database of death registrations and certificates as well as name changes, marriage certificates etc.4. Try to look through the real estate ownership/title search database. It could be by province or municipality. Real estate Lawyers have access to it.5. Contact CIC and ask if the have landing records for this last name (I believe you have to provide proof of relationship). Не знаю, каков был иммиграционный процесс 70 лет назад. You will have to search refugee and or landed immigrants and temporary visitors databases.6. Check RCMP database for any records of him and criminal convictions.7. SIN secured database and social securities payments including pensions.8. Military service and veterans' databases.9. Driver's licenses database.Удачи