Right ventrical hypertrophy is not so much a disease as a symptom from an underlying disease.
The right ventricle can get thickened because it has to work too hard. This can have various causes, like a ventricular septal defect, valve problems etc.
His cardiologist will run some tests to find out the real cause.
I do not see a direct link between his RVH and his learning problems.
If he is not feeling well though from whatever it turns out to be, I guess that could be a distraction from learning?