Now for the long-term consequences:
It's very possible that there will be zero long-term consequences of this injury. It is slightly possible that he could have a few of the following things happen:
1) the permanent tooth underneath this baby tooth could have suffered some damage. You will find this out whenever you get his first dental x-rays of this tooth. If this has happened, there is nothing you can do until the tooth comes into the mouth, so please don't worry about it. It's about 5 years in your future.
2) This baby tooth could die, meaning the nerve inside it was severed by this injury. If this happens the tooth may change to a dark gray or yellow color. If you see ANY signs of infection around the root area of this tooth (that would look like a little pimple on the gums), get to the dentist ASAP. The baby tooth needs to be pulled if it gets infected so that it does not spread to other areas.
Other than watching for a pimple-infection or changing in color, once you're past the initial few weeks of stabilization, you can return to business as usual. You will know more once his baby teeth start falling out, and the permanent ones start coming in (around age 6-7 years).
Do you have any questions for me?