Bank guarantee is one among the loan facilities. You cannot view it seperate from the loan facilities. It will be invoked by benificiary and not by the bank. Bank invokes counter guaranantee against you, if the benificiay makes demand against the bank. If the bank guarantee is backed by immovable security, the the bank may enforce it. But your query is not clear if you have with your wife jointly created mortgage or agreed to create it ?
Bank has nothing to do with your difficulties or personal problems. If theaccount slipped to NPA status then the bank may not leave the property. Please ensure to say if your wife being joint owner did not sign the mortgage document or not. If she has not joined you to sign the mortgage document, then the bank will have to face problem in selling the mortgage property. But your query is ambiguous on this point.
How do you expect the bank to release your document when it has to recover its debts from you. It's strange demand for you. Since the matter is before DRT you may discuss this problem with him and take action if it is acceptable to you.