What you called heart sores are more likely a gastronic problem. Make certain that he has meals at regular hours and plentyful of vegetables. His weight is on the low side. You should also pay attention to complaints about headaches and check his pulse rate regularly (for this you may first establish a baseline after a relaxed period, for example, a long weekend of vacation without stress). If during a busy week his pulse rate goes significantly higher (say over 10beats/min) then he is overburdened. Elevated heart rate is not only caused by physical activities.