Welcome to the forum.
Dark spots are due to hyper-pigmentation of the skin due to over exposure to the scorching sun heat, side effect of some medicines like tetracycline
,etc, trauma, post inflammatory wound, infection of the skin and premature aging is also an important factor.
Irritable mood can be due to inadequate water intake, stress, hypertension
, diabetes or any other pathology which has not been diagnosed. Help your husband take plenty of soup, juice, water, fruits, berries, green veggies balanced with nutritious home made food. Regular showers, exercise, brisk walk and meditation
will help him get cool and relaxed.
To help him get rid of spots, let him eat food rich in antioxidants, vitamin B and E will do him good. The spots can fade away with the help of skin lighteners, pigment reducing agents, skin brighteners, etc. Consult a counselor and a doc to get anti-aging
treatment done. Take care.