Hi I have question how to answer this question about Legality of Objectcontract?

15. Mr and Mrs Sarnath migrated to Australia from Sri Lanka in 2005 . They are dependent on their only son , Jayantha , for advice and support . They have limited education , no business acumen , poor language skills and their only income is the aged pension . They own their own home , which is valued at around $ 400, 000 . Jayantha is a charming but feckless businessman , who is always on the verge of something great . In June 2012, he needs $150, 000 to pursue a dotcom opportunity that will make him rich . He is able to borrow money from the West Bank but only after he persuades his parents to act as guarantors . He misleads his parents as to the extent and purpose of the loan . The bank is unaware of this . After investigating their financial position , the bank manager meets with Mr and Mrs Sarnath and goes over the guarantee contract . He asks whether they have any questions , and , when they do not , they sign the documents as required . Jayantha uses the money to invest in an internet company . The company is worthless , and Jayantha loses his entire* investment . When he is unable to repay the loan , West Bank looks to the parents to honour their obligations as guarantors . Advise Mr and Mrs Sarnath