let alone at this point in his life. Until he's 7 or older the most common altercations he'll have is some pushing, pulling and maybe a few punches... I wouldn't worry about it.
My brothers and I have taught my oldest two basic Jiu Jitsu, wrestling and boxing since they were young. But, we've never taught them any choke holds... They aren't old enough to know when and how to use it.
I think at this age the important thing to teach boys is to have the confidence to push back if being pushed to punch back of being punched. I do NOT advocate or tolerate any form of bullying or starting of fights. My sons know its strictly about self defense and confidence. Not to be tough guys...