Art,

A lease is not a "real estate" contract. Leases do not have to be in
writing in many locales. Often month to month leases are verbal. It sounds
as if this fellow moved in and paid for his room by running errands
initially. That he is now a deadbeat does not mean that he is not a tenant.
The OP should assume that he is a tenant and do whatever the local customs
require to evict him.
On a practical note it sounds as if the tenant does not have any money
(and so is not worth suing) and the landlord does not have a security
deposit so it would be best to try to ease him out.

Dave M.