There is no "bright line rule" as to what should be considered sufficient "regulation." The key would be to produce evidence that such regulation is required. If the endocrinologist writes that activities should be regulated (most likely with specifif examples, or a statment about avoiding "strenuous activitities") then I would argue this is sufficient for the higher rating.
One issue I see is that this is probably easier on active duty, where profiles explicity limit activities. Once out on TDRL, it can become more difficult to produce this type of evidence. Though, if he has a permanent profile limitation, I would use this to argue the point, in addition to any other evidence he can gather.