3 1/2 yr.grandson with behavior & maybe medical problem

My grandson(3 1/2) cute,happy and smart, is showing severe behavioral problems.  Not anger or temper issues because he seems well adjusted although his mother is recently divorced and the father still takes a very positive and active role in their everyday lives and he and the mother get along well. He has a 5 year old brother that is not hard to manage at all and very tolerant of his brother's behavior.  He is very high strung, constantly busy into anything and everything, will not be quiet or still and he is seems constantly over excited(he takes a good nap and sleeps good at night from 8pm to 6am).  Both his parents are laid back, patient and not high strung. We all have tried so many different discipline techniques (consistantly with time)but with no success.  I am beginning to wonder if it may be medical.  We have noticed here lately his hair thinning in the crown and in the last year or so he has been having a lymphnode in the back of his head/neck that swells and then goes away and comes back again.  He also has a hollowed dark look under his eyes.  His mother just started him on vitamins and Voot (vegetable supplement).  He had his 3 yr. check up not long ago but these physical symptoms weren't that obvious then. I am also wondering about another issue that might affect this.  His dad became a meth addict during the time he was conceived (he is now 2 yrs. sober and committed to helping others rehabilitate).  Would this have any medical affect on this little 3yr old boy?

[RockRose]

meleia,  I'm not really getting a clear picture of what's going on here that he's being disciplined for.  He has no anger or temper issues apparently,  just is high strung and excitable.  Some people are,  and others are lethargic,  and most fall in between those two extremes.  

Could you maybe  be clearer?

Also,  you might want to google Telogen Effluvium for his hair loss.  Did he have an episode of high fever 6 months ago or so?