sec 409, 420

My brother work as probationary officer in deccan grameena bank, joined in 2011, in 2012 himself and two more bank officials did a fraud, modus operandi was accountant misplaced cheque books and altered some inoperative a/c names of customers to RAMCHANDAR name and asked my brother to write unknown bearer names and sign as Ramchandar on cheques n then some outsiders presented those cheques at the bank cash counter and encashed the cheques as the passing officials were the manager and account themselves. One more thing is that bank has no signatures feed in their computers and they dont even check the opening forms of customers to verify the cheques or vouchers while paying cash. But in 2012 it came to light and account and manager were held responsible as prima facie evidence of altering names and misplacing cheque books. they got suspended. Amount involved was 36.60 lak, then they along with some other officials approached my brother to take the entire guilt and to confess that he alone did that by using the I.D of them to log in and change customer names, stole the cheque books and encashed them with outsiders connivance otherwise they threatened to involve him too as his handwriting was on the cheques, they assured of no police complaint by bank, giving money. My bro was just 22 at the time. he confessed in writing to management, got suspended and paid 16.75 lak to bank which was given to him by them in some instalments, but all of a sudden those two men got reinstated and police case was filed on my brother showing the confession letter and money paid as proof. Now Is there any way that those two men who escaped be brought to justice ? hand writing analysis will prove my bro guilty ? but cheque books were misplaced by account for which there is documentary evidence that he was having the locker keys on missing date, and the names were altered in their USER ID's,that evidence is also there. Please tell whether my brother only will be held guilty for everything ? or those two men also will be held guilty? Also note that there is gross neglizence from the bank of not following any minimum security measures like signature verifying and also cashiers never tried to check for identity of outsiders whom they paid the cash as the cheques were bearer, the outsiders are not traced till now, and no chargesheet has been filed, my brother told all the facts to police men, my brother doesnot know the outsiders as those two men only dealt with them. Please tell whether my brother only will be held guilty for everything ? or those two men also will be held guilty? If hold guilty how much can be the punishment to my brother. Please advise me Sir, All your advices will be appreciated Sir. Thanking You All