lien against family member

Well, to answer your question directly – if you want to put liens or levy against your son’s property, you need a judgment (and then there’s a whole set of steps from there).  Now, just because you don’t have a written contract doesn’t necessarily preclude recovery of money that owed (although it does make it more difficult usually).  The aspect of your situation that I would bring to your attention is whether or not this $7,000 would legally be considered a gift.  And there’s some factors that can sway that one or another, but, for example, is this a general amount you’ve tallied from various small amounts/purchases/etc. or was this a lump sum given, say, for a loan?  Another consideration I would strongly urge you to think about is the practical side of suing your son.  Lawsuits can get ugly anyway and generally parties don’t walk away as friends.  Are you prepared for the consequences of a law suit of this nature?  Perhaps you may be able to find another route that would take care things.  However, that’s your call – if you’re interested in what legal recourse you may or may not have, you need to sit down with an attorney in a confidential setting and hammer out the details.  Frankly, I can’t say if you have a lawsuit, but it is possible.  To avoid potential statute of limitation issues, I would advise having a consultation sooner rather than later.