How big is your condo building?
He'll want to make sure that whatever vote was taken was done properly, and according to the bylaws. And that a sufficient majority voted for the new bylaws.
He'll also want to check to make sure that, regardless of whether the vote was "proper," that the condo association has the authority to take such an action.
I'm not a lawyer, so what follows isn't legal advice. However...
If all else fails, read the new bylaws carefully. If it says something like "All units must be occupied by an owner of the property" (the key concept I'm getting at is that if their restrictions says only someone who has an ownership interest in the unit can reside in that unit), check with your lawyer to see if this strategy will work:
You create a land trust (an "Illinois style" land trust) for each condo unit. You transfer ownership from yourself to your land trust. People transfer properties into their own trusts all the time--often for estate planning purposes, sometimes for tax purposes, sometimes to preserve confidentiality.
So, now each condo is in its own land trust. Your land trusts.
Then you assign a 10% beneficial interest in each trust to the respective tenant. The paperwork provides that when the tenant moves out, the tenant transfers his/her ownership interest back to you. So now each trust has two owners: You and your tenant. Aha! The tenant is now an owner (a 10% owner) of the trust that owns the unit. Thus, a 10% owner of the trust is living in the unit.
Next, the tenant leases the unit from the trust (of which he's one of the owners). The lease payments go to the trustee (a third party...it can't be yourself), who then writes the checks to pay the mortgage, condo fees, and other expenses. If the lease payment from the tenant beneficiary isn't sufficient to cover all the expenses, then you'd pay the rest by sending a check to the trustee.
Now, when the condo association says, "Only owners can live here," you respond, "The person in that unit is an owner of the trust that owns the unit. He is an owner."
More information on land trusts at http://www.landtrust.net
Hope that helps.
I agree with Mwass - in all honesty you are best off consulting a Real Estate Attorney with this matter. Some questions to find the out the answers and more details about is - obviously can they do this... are you somehow grandfathered in... did the association have a closed door meeting (big no-no imo)... is there a difference between amend/extending your current lease for years to come (including continuing sub-leasing) or does that create a new lease etc... Most likely this is btwn you and the association and not association with the tennant.
Unfortunately you have a unique situation which there isn't a blanket answer so that's why it is best to seek legal counsel.