Hi There
I would have to say, that I wouldn't choose to employ someone in active addiction.
You truly may be putting yourself and the business at risk, plus he is unreliable.
All drugs are mind altering, but my experiencee with my son, has been that some have a more devastating impact on personality and behaviours. They appear to lose total control of it - putting you in a very vulnerable and dangerous situation. You won't know when the bomb is going to go off.
Of course, the choice is yours to make, but I would consider this very carefully to protect yourself and the business that you have worked hard for.
Much Love
Bute x