If the house was in his name only, it was not, we are sorry to say, your house: you were not an owner and had no legal right to or interest in it. It was not your house. Guarantying a loan does not make you an owner or give you any rights to the property--all it does is make you responsible for paying the loan if the primary borrower fails to do so. So yes, the bank can do this, because they do not owe notice to a non-owner of a house.If you were on the title or deed, that would be different: then it would be your house, too, and they could not foreclose without giving you notice and a chance to other pay off the loan or have your day in court. If you were on the title, you should be able to get the sale set aside or at least get a substantial amount of monetary compensation; so if you were on the title, consult with an attorney about legal action.