This is a sentence from Dickens's 'A Tale of Two Cities'. It's from Chapter 11 of Book II. Mr. Stryver accused Sydney of not being agreeable in a women's society and he told Sydney that he felt ashamed of Sydney when they were both with Lucie. Then Sydney rejoined:"It should be beneficial to a man in your practice at the bar to be ashamed of anything."
This ironic sentence should mean:'It's good for a lawyer like Mr.Stryver to actually feel ashamed about something.'
But then why did Dickens use the preposition 'to' here? Should he have used 'for'?
As an ESL speaker, I usually think that 'it is beneficial to somebody to do something' means that 'Doing something does somebody good.'
Is it still a valid prepositional use in modern English?