Bankruptcy Law Questions? Ask a Bankruptcy Lawyer.
The presumption is that the money left in a joint account is 50% yours and 50% is hers. However this is a rebuttable presumption.
You have to list the joint account in Schedule B and then claim zero as your interest. Just make sure that you clearly state on the description of the assets how the funds belong to your spouse only and be prepared to show the documentation regarding the sale of the flat to the bankruptcy trustee if he or she requests it.
If you do not have any assets in the US at this time, you might not be able to file for bankruptcy protection in the US. In order to be eligible to file for US bankruptcy relief, you must be domiciled in the US, or have property in the US, or have a place of business in the US.