If you want to still have this person in your life, confront them and tell them that you care about them but that you don't appreciate being used. If this doesn't help, make a new friend...: )
A parasitic friend is no longer a friend. A friend in need is a friend - either you are in need of s/he is in need.
Parasitic? why would you call someone who exploits your hospitality a friend?
Why would you allow someone to exploit you or use you?
You need to tell them you are not comfortable with your friendship or just distance yourself from them.
Get rid of them before they make you a use and throw pen.
drop them like a bad habit. but wait, bad habits are hard to break....a conundrum indeed!
Say exactly what your trouble with him is... And for big issue's make legal contracts. It'll keep the both of you on agreements.