The tenant has had a full year, at least, since his last move in which to save up the necessary funds for the SD. If he hasn't done it in that time, it speaks volumes about his ability to handle money. Pass on this one unless you want to chase him all year for rent and anything else he's responsible for under the lease.
Forgot to mention the LL's creed: No good deed goes unpunished. My theory is that surely someone knows the tenant better and has greater reason to trust them than you, right? Why isn't he getting financial assistance from that person? The answer to that question also speaks volumes about the tenant.