Can my landlord not allow me a caretaker for 12 months as prescribed by my doctor?

Your question doesn't mention the details of the problem with your Landlord, but it sounds like you may be describing a conflict over a live-in care.

Gather the facts of your situation, and contact the legal aid office in your city or town. Ask for an attorney who is experienced with Landlord Tenant law. There may be remedies available to you under federal and state laws that protect people who have disabilities.