Tell him, he still recognizes the ganja for it's goodness. One thing I learned is that any one who smoked weed in the past and still understand how it is a good thing will respect the fact you smoke as long as it's the only drug you do, I told all my aunts and uncles on my moms side of the family and they don't care, they use to blaze together. Hell, one of my aunts said I could crash at her place if I was too drunk or blazed to be at my house.