I got 3 root canals 2 years ago, just keep your teeth clean and it should be fine...

But if he took the root out of that tooth, it most definitely needs a crown. Teeth without a root will become brittle and break. If he didn't drill down to the root, then a simply filling should be fine as long as it's done correctly(I have a crummy filling from a dentist I hated and there's holes between it and my tooth that I can feel, I have to go in and get it checked out)