I have been asked to make a wedding cake that is diabetic friendly. Please help me with a good recipe for cake and the icing. And they want it white!! HELP!!! 

Try to get the Pillsbury "sugar free" cake mix and icing in cans.  These have the conversion for diabetic servings written on the packages, and they have posted the exact list of ingredients online.  

If you have to bake from scratch, you need to use google to find the recipes.

In both cases, show the list of ingredients to the bride for her approval BEFORE you sign this contract.

AI have looked for the white diabetic mix but can't find any. All I can find is yellow and chocolate. So that's not good for me

Have you tried going on line and searching diabetic recipes for cakes???  They will also give you all exchange and nutrition info.  The trick is to try some of them and find out what tastes good. 

  Would 1 layer of this type of cake do for whoever eats it?  The other question is will these type of cakes stack?  For goddaughter's wedding I made a seperate gluten free cake for some guests and family... labelled it and had it served just for them.