Too much protein by anyone with kidney issues is problematic, but the source itself whey protein isolate is an excellent form of protein.   Think of it as a food supplement, that has many properties good for balancing blood sugar etc. HOWEVER, whey protein isolate taken by itself may not be a good option for someone with diabetes/insulin issues as it may cause a drop in blood sugar. Be sure to have it as a balanced meal with some "good" fat (Chia seeds are excellent, almond butter, etc) and low to medium GI, fibrous carbohydrates (frozen berries, yam, buckwheat etc). Assuming you are healthy, 20-30 grams of whey protein isolate should be fine. 

Keep researching and consulting a naturopathic doctor or sports nutritionist/regersited dietitian who has a degree in nutrition/dietetics (versus someone who just took a nutrition course and is now "certified")would be a wise choice.