In my humble opinion, your friend is daring the Justice Department to prosecute him.
The advice you and he need are far beyond what you can get here on AVVO, although the lawyers here are top notch.
There is recent NY Times article on this. Go find it and then go find a team of lawyers to give an opinion as to you friends criminal exposure.
I published a law review article on medical marijuana in Washington state. You can find a link to the article on my profile under "Publications."
You may find the article helpful, but it's generally published for a legal audience. If you want a personalized consultation regarding medical marijuana, you'll need to retain an attorney.
And I'm just chiming in to add that WA provides immunity to landlords for issues directly related to the tenant's decisions. I am not promising you anything, I am just saying there are cases out there where tenant did something, third party sued tenant and landlord on the theory that the landlord was responsible as the owner of the property, and the WA courts consistently say that conduct under the control of the tenant is *not* attributable to the landlord. See Frobig v Gordon, which involved, I kid you not, a tiger.
But I can also promise you that 99% of the commercial/residential tenancy issues I see happen because somebody took legal advice from their buddy the real estate agent, and thought they'd save money by not hiring a lawyer. This is not a good decision. So much could be saved with a consultation first!
Using Avvo does not form an attorney client relationship.