Mold found as a tenant

[Chris Starling]

I have a friend who moved into an old house as a renter in Western North Carolina ~11 months ago along with a roommate who moved in who has been there for 2 months

Both of them recently have been reporting symptoms associated with exposure to mold lately such as a deep cough, fatigue, joint stiffness, and dizziness.  She changed the air filter to the AC unit and there was mold on it. Also after doing some investigating in the basement It looks like there is mold in the basement 

She's not sure if the mold is causing health issues -- thats not the main point here.  It's more that the landlord doesn't seem to be taking this seriously.  When asked about testing the mold the landlord mentioned they can't afford testing. So my friend is not really sure if the mold is harmless or harmful.  The landlord has offered for them to terminate the lease without penalties if they want but it seems like pretty nuclear option to go to right away. Is it the landlord's responsibility to test the mold?

I was hoping to get some ideas from the forum to see what other options are as a tenant in this situation? Also maybe get some North Carolina specific resources to look into that can help determine a path forward?