No, you may NOT put a lien on person B's property (e.g. his parents) for something person A (e.g. your partner) owes you: you can lien (or attach, execute on, garnish, etc.) something someone *owns*, not something they rent. If you know where his bank account is, you can go after the money in the account; if he owns valuable personal property (e.g. an expensive TV or gaming or sound system; fine watches or jewlery; etc.), you can try to go after it; if you know where he works, you can try to garnish his wages--but it has to be *his*, not someone else's.Also, you first have to sue him for the money he owes you (such as for violating his agreement about refinancing the loan) and get a court judgment against him (an order that he must pay you money due to his breach or other wrongful act) before you can do any of the above; a private citizen may not seize or garnish another person's assets or income without a judgment in her favor.