He will remain liable for the loan. Your filing bankruptcy does not increase or decrease his liability to the bank because he also promised to pay the bank.
IF you are paying a debt back in a chapter 13 bankruptcy payment plan then the banks cannot try to collect a debt from a cosigner while you are making your payments, BUT if you do not have to pay back all of the debt in the plan then the cosigner is liable for the difference when the case is over and the creditor can go after the cosigner.
