Guarantor employee became pensioner

Sir, This ramesh. my father signed as one of the guarantor(2 guarantor's) for an education loan of his superior( for superior's younger brother) around 2006 in sbi. after one year (2007) his superior resigned his job and left the location where he worked. my father informed to bank that he is leaving from his service and relocating to another place. bank officials have not taken any action about that matter. we knew that he is residing at saudi arabia. the bank officials enquired in passport office. the passport office replied that there no person with this name in our records. i have enquired his address given in his service book. i knew that it's fake. in 2010 the bank official forced my father to repay the amount around 1.8 lakh(including interest) by salary cutting, otherwise we will stop the benefits of retirement. then he wrote a letter to bank that deduct an amount of rs. 3000/- from his sal. at that time his salary was 12000/- pm. they deducted the amount approximately 5 months. they forgot to deduct. in 2012 he retired from his service. now the account was inoperative since last one year. he is now drawing his salary and pension from a joint account of me and my father since 2007. recently he applied for a pensioner loan on his pension. The bank officials credited the amount in that inoperative account, they asking for amount of that defaulter amount. if u pay the defaulter amount we will release the loan amount otherwise we will adjust this amount for that defaulter loan. here i want to know that is it pensioner exceptional for this kind of defaulters loan as he is a guarantor. or any other solution for this matter.