From a high level perspective, I agree that insulin causes the body to burn blood glucose for fuel. The extra "carbs" don't get magically converted to fat though - they're used to replenish muscle glycogen and perform other actions. It is the dietary fat ingested alongside carbohydrates that gets stored as fat in the body.
Here's a quick summary: http://examine.com/faq/how-are-carbohydrates-converted-into-....
Note: I am not an advocate of ketogenic or otherwise low carb diets. I think a calorie deficit and adequate protein intake is all that you need to lose fat. No diet can work without some sort of calorie deficit, either explicitly or indirectly induced.
No, it will confirm what he said and that you are mistaken. You should try opening one and skimming through it before believing it will always support your assertions, regardless of their lack of factual basis.
Carbohydrates ARE converted to fat under normal dietary conditions, via insulin. If this metabolic process was "rare" as he states, then diabetics that require insulin injections wouldn't need them often.
I don't know where this "expert" is getting his information from, but it's a basic human biochemical reaction to form fat from blood glucose, via insulin.