The cream etc isn't so bad if he doesn't have a weight problem, but being overweight isn't good for diabetes, so I would keep it as an 'everything in moderation' thing, rather than make him feel that he has to give up everything all in one go.
Switching to wholemeal bread/rice/pasta is important though, as white gives huge blood sugar peaks and troughs, which are bad for long term health.
He needs to be aware of the signs of having too low blood sugar, and make sure that he carries something sweet with him to have in case of a hypo, so ensure that he doesn't pass out from one.
If well controlled then there need be no long term health problems from it, but if poorly controlled then there are risks to kidneys, eyesight, poor feet and a range of other stuff that isn't quite springing to mind.
Have you had a look on the diabetes UK website too? They have a forum there as well which you may want to post on.
(Lots of diabetes in my family, including brother who has been type 1 since age 8, and I currently have gestational diabetes, which is controlled similarly to type 2).