If they bother him from time to time when he is awake, it could possibly be RLS, but that is also kind of vague.. I guess the real test is, if its not bothering him to the point where it keeps him awake or otherwise distracted and uncomfortable, you should consider the possibility and maybe educate yourselves a litte, but in general not worry about it until it truly becomes a problem. Then you'll know how to deal with it and what kind of doctor you'll want to go see..
As for his legs shaking in their sleep. It is likely Periodic Limb Movement Disorder. People who have RLS also tend to have PLMD. However neither condition leads to the other. If its not affecting his sleep too terribly and he isn't complaining of being tired, and it doesn't bother you, then you can also just let it go, but educate yourself and be aware incase it does become a problem.
And in any case you should report these symptoms to a doctor. If treatment is desired or necesarry, that will you'll get the help you need in any situation.
The forum is pretty straight forward.. The main page is
http://bb.rls.org/index.php
That shows you an index of all the forum categories.. This is the Non-Pharmaceutical Therapies section, for people looking for possible remedies with over the counter supplements / natural plants & chemicals.
The category names are pretty straight forward though, so it shouldn't be hard to get around once you stop and read them for a second.