I no longer have children anywhere near school age, so I'm pretty much out of the loop on this. What are you thoughts about young people learning English? I wonder if your immigrant ancestor from Germany still spoke any German to his children?
There's one theory that total immersion is most effective and others maintain that bi-lingual education produces good results.
This thread does make me recall the scene from the classic Casablanca where the German couple at Rick's is about to depart for America.
My general sense is that the whole family pretty much spoke German at home until the outbreak of World War I made it wildly unfashionable.