Whether the judge(s) cited an actual statute or simply legislated from the bench I don't know, but regardless of the reasons for this decision, we can say for certain that there is no Rule of Law in Germany.
"A German federal court has ruled that a man must pay the cost of old-age care for his late father, who severed ties with him more than four decades ago.......
The man's parents divorced in 1971, when he was 18. His father broke off contact the following year and later wrote a will naming a female acquaintance as his heir.
The court found that although the father broke off contact, he fulfilled his parental duties while his son was a minor."