Yes, this can be a very upsetting event for the family.  However, it may be able to be redesigned as an opening for empowerment and healing.  Consider these suggestions and ideas.

Many school districts today have anti-bullying programs.  If yours does, you may want to request a meeting with the school personnel involved in your sons' incident and find out the reasons they handled this the way they did.  They may have been following anti-bullying principles.  It is generally considered that meeting violence with violence is not the best strategy for dealing with bullies.

If you school district does not have such a policy, this may be a moment for helping to get one put in place.  Education is considered the best plan for stamping out bullying.

Also consider this point.  Since both your sons have had upsetting experiences, might some outside professional help be a good idea?  It is always wise to help children, and maybe yourself as well, to work through a traumatic happening.

Whatever you do, please consider educating your kids about the best ways to deal with a bully, such as reporting (not considered "ratting on," or "tattling") to a safe adult.  There are other good ideas on this website. You can search under "bullying."
Good luck and let us know how it goes.

Bette J. Freedson, LICSW, LCSW, CGP
Clinical Social Worker
JustAsk Expert
http://www.singlemomsos.com/index.html