So what about all the teachers who was trained in Delphi. I bet a lot of schools also prepared for the change.
Just another sign that our education system is in serious trouble.
I was at the point to start training my son (Grade 10 next year and doing IT) in Delphi. Good thing I waited.
I think you (or your son for that matter) dodged a big bullet there. You're right, "what about the already trained teachers" but the fact of the matter is that the software development world is moving really fast, and Delphi are in fact dead. You'd do way better teaching your child something else - and by something else you should research what is the best open source and/or widely available languages out there.
We did Pascal at school, and even though it taught the basics, it wasn't something I could use after school AT ALL! Because by the time we ended school was the death of DOS and the dawn of the second and third generation Windows (Graphic).
My suggestion would be to do a language that:
1) Can be used for something real-life even after school (with Delphi, if you don't buy Delphi after school then sorry, game-over). Java is at least free to use. PHP (even though it's old) runs a major part of all websites online. Sure, .NET is an option, even though I'm not a Microsoft lover. Heck there's even things like Ruby-on-Rails.
2) Get something that you don't NEED a specific OS for. That's one of the reasons I dislike Delphi and .NET... because they're Windows bound. So if your kid gets a job at a place that gives him a Mac - or he doesn't have the money for a Windows OS or a Mac and installs Linux, then he's screwed? No, rather pick something that's cross platform. Java is nicely cross platform. So is PHP, so is Ruby, etc.
Hit google up a bit and see what you find. Again, I think you dodged a bullet.
(Don't get me wrong, I thoroughly enjoyed Delphi at University... but that was in it's last few years of life)