Thank you very much for your suggestions. I shall ask him to try out the sentences as you suggested this coming weekend.
I somehow think, however, that it is only during certain situations such as on the telephone to an 'elder or better' that he goes into an auto-mode of speech so I am unsure if doing this between the two of us would bring out his errrish self. No matter I'm sure it will get him thinking about it more and perhaps building up the routine in his thought processes will help in the long run.
Should things not improve I shall not hesitate to get in touch.