Sometimes the kids need to take a few lumps on their journey in life just like we did. You made your worries known to him now it is up to him so wish him well. He is 25 after all.
Who knows what new doors may be opened to him now? New ideas, new critical thinking skills, etc.... who knows? he may even decided an entirely different course before he is through.
Wishing him all the best and for you some peace from your anxieties. It will all work out.