I'll address this from an "insider" position.
Bank staff are no less vulnerable to debt problems than any other members of society. Your friend is not in any worse/better position than many of his colleagues. Bank management are well aware of the potential difficulties for staff and all of the major banks have a policy on dealing with staff members in difficulty. The main risk here is that a staff member in financial difficulty may be tempted to dip into clients funds, as an option, rather than addressing the issues with Bank HR.
Please advise your relative to approach the Bank HR staff on this issue. It will be dealt with sensitively and privately (without direct managers being informed) and if he co-operates with the system a satisfactory resolution can be reached. His career prospects are more likley to be damaged if he fails to deal with these problems, than if he uses the system that is there to help all staff in difficulties.