This is stanchart's risk management strategy. They contract with a law firm that will give them a good price for generating these lawyer letters. The lawyer letter is basically a scare tactic by the bank. Most othe financial institutions do not even bother with the lawyer until you are way behind, or they cannot contact you, or cannot reach an agreement with you, etc. stanchart knows that if you are behind in payments to them, than u are probably behind to other creditors too. They want to scare u into putting them first in your priority for making payments to your creditor. That way, if you have spare money, u will pay them first before others.
This is new to me, their divergent from standard practices.
Such a practice has a fallout on their customers. The fact that one bank takes a legal suit against the customer will be quickly known by the other banks as such suits are watched daily. They will check their records and once they find you are also past due, they will not hesitate to write letters too. Because the bank that goes first past the post will have the prime pickings in a writ of seizure and sale.
In any case whether a person is past due or not, a credit check can easily tell the whole story. In your friend's case, you might like to find out if he owes other banks more than 90 days. If yes, following your reasoning, a bank might like to shoot the first arrow to get the prime pickings. Otherwise, it does not make business sense to do such things. A bank values its reputation.