Payment of loan amount

Sir, my friend marry with a women who is central govt employee, my friend also employee of same office and work below then his wife post. that they are jointly purchased a flat through bank loan, but unfortunately his wife left his house without any probable reason. but now she filed a case for their minor sons maintenance U/s 125 Cr.P.c and also file a case of D.V. Act with allegation for domestic violence against his mother in law and against my friend. that now my friends wife intentionally disagree to repay bank E.M.I. amount and not also agree to sale the said flat. that she also deduct her salary in different fixed deposit and savings account. that due to such reason my friend face a monitory problem. but he pay the bank EMI proportionately according to equal ratio. but due to non payment of 1st borrower (my friend wife) the bank has issue notice for payment of EMI. hence for above situation what legal action will be take by my friends for non payment of EMI and how can he attach his wife salary for recovery of bank loan according to her share of property.