Underwriting is simple only for the 100% great apps and 100% horrible apps. Once you get into the middle, there are many compensating factors to consider.
Are there exceptions allowed by your policy? Would the exceptions be offered to all applicants? (Is there a centralized underwriting to determine if someone was declined for basically the same reason that this loan is being recommended to be approved? ) Are their similar products or conditions to make the loan.
It would come down to were different applicants treated differently? If someone else was declined, and this one made, you have an issue. If the bank elects to make this loan (HELOC), then, in a comparative file review, they just lowered their lending standards. (Comparative file review looks at practice, not policy.)
Integrity. With it, nothing else matters. Without it, nothing else matters.