Are creditors able to come after you for debt that was acquired prior to establishing a sole proprietor ship?

Unless discharged by bankruptcy, barred by an applicable statute of limitations, or otherwise voided or set aside, you remain liable for your prior debts even if you start a new business -- regardless of the form of that business. If the new business is a sole proprietorship, the assets of the proprietorship will be subject to the claims of the proprietor's creditors, including creditors who acquired their claims prior to the formation of the proprietorship. There may be ways of making arrangements with the creditors so that they do not seek to attach the assets of your husband's new business. Those kinds of arrangements are best made through an attorney. They will, in any event, depend on the voluntary cooperation of the creditors.