Legal Question in Bankruptcy in California

Even if you were to become saddled with debt because of your relationship with this individual, I doubt it would have any immigration consequences unless you committed some crime. But I'm not an immigration lawyer.

What do you mean, he is "bankrupt"? Did he already file for BK or is he just indebted? What do you mean, "the business is in both your names"? To lawyers, there's no such thing as a "business." There are only sole proprietorships, corporations and partnerships, and you don't want to be anyone's partner. Especially this guy. If it is determined that you are partners, you would be personally liable for any and all debts he incurs in the name of the partnership. I would also want to find out exactly why the guy is bankrupt. Is he a coke-head or compulsive gambler? You need to get to know him really, really well, including looking up his bankruptcy schedules, credit report, and especially his criminal history, before you open a bank account or otherwise become financially intimate with him. Ask him for written permission to access his credit and criminal histories and for copies of his tax returns for the last few years, and then go to a company like ChoicePoint. If he is hesitant to give you this information, hang on to your wallet! If he has bad credit because he burned all the banks and credit card companies, guess what? You're next! If, after doing your diligence on this guy, you still want to go into business with him, have 1) a corporation or LLC that issues shares to each of you; and 2) a contract that you paid your own lawyer to draft.