What are my options if my brother refuses to sign the mortgage papers?

  I'm a little unclear about your deed. You say "The deed states tenants in common with life estate to me." This suggest that you own a life estate, but  I expect that you own more than a life estate as banks will not usually lend money to owners of life estates .    You should have an attorney look at the deed . However,  to answer your question , if in fact you own a property with your brother, then he must sign any mortgage on the property as well. There is really nothing you can do about that. You could buy him out but if he refuses, you'd have to sue him for partition of the property by the court.