dark circles may be caused by different things. It may be hereditary, liver related, heart related, deep sleep related, stress, diet, you name it. It is best to find out what is causing his dark circles first and then seek action.
In the mean time, to cover up, the best concealer I ever tried is the one from Bobbi Brown. Creamy concealer kit. It's perfect
2C-3A. PW: on request
Love:Jessicurl WDT+Too Shea, Coconut Oil, Aveda Rosemary Mint shampoo, BRHG and Curls Rock Creme.