I'm :laugh:ing hard at the general ignorance in this thread.
Ignorance: ?noun: the state or fact of being ignorant; lack of knowledge, learning, information, etc.
Anyone renting to college kids, AND their lawyer, property manager, etc are well aware of ALL the possible negatives that come with renting to young people with no/hanging by a thread jobs, no skills and zero dependibility. I guarantee you that the wording of the lease leaves the original lessor or lessees (sp?) 100% responsible for all rent/deposits/damages. I.E. the OP, being the sole, original signor of the lease, is on the hook for it all.
The OP was ignorant when he sublet to a friend of a friend with no security deposit required. What young people don't understand (I didn't either, 20 years ago) is that business is business.
Here's what should've happened when the OP was thinking about letting the bum live there:
/flashback swirly sound
"Uhm, hey, Bob. *young people high five/handshake/gang sign* I know, like you're all Tom's friend and all but like, I'm the name on the lease. If you're late on the rent, I'm locking you out of the apartment until you pay it. Sorry but that's the way it is...if you can deal, then you're in."
OP is ESPECIALLY ignorant if he was able to pay the rent by himself but then got himself into the situation anyway.
Good luck, OP. Roommates suck. I lived alone from 1996-2006...after getting screwed over by roommates, of course. We all have to learn the hard way. I hope you have.