Lemonie, statins apparantly have a secondary effect of protecting against heart conditions, even when your cholesterol is fine. And as you are high risk on both sides of your family if it were me I would take the tablet, well actually I have taken my statins.
The safe cholesterol level for diabetics is lower than the general population and 5.8 is quite high. Having said that mine came down from 5.4 to 4.2 simply by reducing my carbs,even though my cheese and diary intake had rocketed. So lowering it is not impossible but I decided that even with the reduction. I wanted as much protection as possible for my heart.