I have seen several cases where the feds 'refused' to get involved, because the "count" was too low. One, not so far from me, consisted of over 30 plants(we are allowed 6 mature plants). The local SO busted him, but the feds refused to prosecute it, becuse it did not meet 'their' criteria in numbers. The 'grower' alledgedly had caregiver cards to cover the numbers. The case is still in limbo at the "state" level.
There are also plenty of cases, where states have fought the fed's, and orderd the return of the med's and grow equiptment. (not that it ever happened, but at least the states are standing by "their" laws)
I'm NOT an attorney, but my thoughts ... If your roomy has a med card, and remains within the legal guide lines,I'm not sure that the landlord "legaly" can't do a thing about it within your local jurisdiction. He is "protected" by the law.. IMO. Local leo's hands are tied. They "must" uphold the law.
I've never heard of the feds getting involved in tenant/landlord eviction cases.And like I said before, "usually" are required to meet certain criteria(numbers) before they will get involved. In "most" cases, they are not interested in "trumping" local or state laws in med approved situations.
I'm not goiing to say it will never happen, or that it couldn't happen. Or that it wouldn't cost you a few grand in attorney fees. But I do believe that a 'good' mouthpiece could beat it, as long as "you" are not involved in the meds in any manner.
"His" grow should be in a locked room, with his med permit posted in a clearly visible location.
If I were you, I would look into applying for a "caretakers" card. I'm not even sure that you could/would qualify, but IMO, would be worth checking in to.
That should protect "you" from prosecution of 'his' grow.