Santander overdraft

Nebulous2

The debt free wannabe section of this forum might offer more practical solutions to your sons problems, however I would say that banks are not mind readers. They wouldn't know your son was in trouble unless he told them. 

I think all of my bank accounts emailed me during the pandemic to say if I was struggling let them know and they would help. Approaching them and asking for help would have more chance of getting interest frozen than a third party contacting them and demanding a reduction in the debt. 

The other nuclear option is to stop paying. That would get their attention, would eventually lead to the account being defaulted and interest frozen, but would have an impact on his access to credit for a long time.