During any time that any such loan is outstanding, the Secretary is authorized under regulations to be prescribed by him to grant a moratorium upon the payment of interest and principal on such loan for so long a period as he deems necessary, upon a showing by the borrower that due to circumstances beyond his control, he is unable to continue making payments of such principal and interest when due without unduly impairing his standard of living. In cases of extreme hardship under the foregoing circumstances, the Secretary is further authorized to cancel interest due and payable on such loans during the moratorium. Should any foreclosure of such a mortgage securing such a loan upon which a moratorium has been granted occur, no deficiency judgment shall be taken against the mortgagor if he shall have faithfully tried to meet his obligation.