Alice,
Check out the landlord tenant laws in your State. Most States have a whole rigmarole a landlord has to go through before someone can be evicted. (Ask some of the people here who have wanted to kick someone out of their home!)
The process can take months and months. Not so good if you're a landlord, but the laws are made to protect tenants. You DON'T have to honor his notice, I believe. Do a little online research, and possibly speak with a landlord/tenant attorney (a consultation shouldn't be costly). If you qualify, Legal Aid usually has landlord/tenant lawyers on staff.
Hugs, it will be OK.