Oliver Prinz von Anhalt was involved in a motorcycle accident on the day his stepmother died, and his father tells TMZ he never recovered from his injuries and passed away on Christmas Day (25Dec16).

Zsa Zsa died after suffering a heart attack on 18 December (16).

Frederic insists he wasn't even aware his son was in California until he received a call from the coroner last week (beg19Dec16). He had no idea about the accident.