Tara, as to if he should stop or not, that is a personal decision, most likely discussed with his Neuro or PCP.
What exactly are the reasons he doesnt take it? does it make him jumpy? hyper? sleepless? drowsy? From what I have read it is important to take LDN on a somewhat strict schedule, once the reasons for not taking it as prescibed have been concluded, perhaps check with your doctor for possible additional treatments to the negative effects.
I have read where many have found different amounts, as per what is taken ,work better for some and less for others, 3.0 works for some, 4.5 for others, and in many of the forums It seems adjustments are often made to see if it can help with progress or negative aspects such as you have mentioned.
As I stated, perhaps once the reasons for not taking it as scheduled are specific, then look for options that would make it work out better, where there is a will, there is a way
, or so we can hope..