I think most times the "logic" of an enabler has to do with fear of abandonment within the enabler. In that system of logic, to become enmeshed in the life of another brings a (misguided) sense of security - that it is harder for the second party to abandon the enabler if the second party is "dependent" upon them. I think this "logic" is often subsconscious, not on a conscious level.
JMHO
CLMI