your symptoms can be due to telogen effluvium. The growth
cycle of hair
is in two phases, anagen or growth
phase and telogen or resting phase. During stress or when the immune system of the body is lowered many hair enter the telogen phase at the same time and can be shed. Hair takes between 3 and 6 months to re-enter into growth phase, so the restoration is a bit slow.
Eat a healthy balanced meal, use mild shampoo and lather gently and rub gently with towel to dry his hair.