Would you be thinking of letting the room, or using it yourself if his things were not there, what about the insurance aspect of keeping his belongings in your house, how will he pay you, how long exactly will he leave his things there, you dont want to be stuck with them indefinitely?
just some questions i'd be asking him before letting him go on merry way, how long will you let him stay rent free when he returns to find a job.
Think seriously about the implications of doing this.