I think you might have a misconception involving the different types of ketosis. For Type I diabetics, there is the danger of ketoacidosis, which is what happens when the body produces ketone bodies because it thinks there is a low blood glucose due to the lack of insulin, with the excess ketones acidifing the blood. What paleo people talk about here is ketosis, where the body uses ketones for fuel, which is perfectly normal, and safe. Often ketosis is referred to "keto".

I've read some success stories of people doing "primal" and/or paleo while having type I. I did a quick google search, and got some results. What is interesting, is that the type I diabetics eat a lower carb diet, even going into ketosis, and since they keep their blood glucose lower by not eating a lot of carbohydrates, they don't run into trouble with ketoacidosis.

Edit:
Reading the first hit on the google search, you can scroll down to see the amount of carbs he was eating, with him eventually eating below 100, which would mean he would be getting into ketosis, or very close to it.

Hi! My name's Samantha, I'm 22 and I've had Type 1 diabetes for 18 years. When I first found out about Paleo/Primal nutrition about 2 years ago, I was intrigued. After doing a lot of research, reading many books, and even speaking directly with Robb Wolfe, I decided to try it. I immediately saw great results. My a1c went from mid-9's to a 7.0. I effortlessly lost nearly 30 lbs (put on after years of being a collegiate rower and eating tons of carbs each day). While my body was first adjusting to this vast change in dietary habits, I was producing ketones, although my bg's were always below 200 (and often 80-140). My Endocrinologist (Director of Endocrinology at Georgetown University Hospital) agreed that this was a safe and natural process. (He was wary of the lack of grains in my diet and the high amounts of protein, but I decided to follow the paleo tenets and ended up with great results). As mentioned above, ketosis and ketoacisosis are two very different things (just as Type 1 and Type 2 diabetes are two very different, yet similar-sounding conditions). The biggest challenge for me was determining how much insulin to take for very low-carb, high fat/protein meals!

If you or your son would like to speak further, I'd be happy to give you my email address and/or recommend some resources. I've done a lot of community outreach/counseling through JDRF, so I'd gladly discuss. I wish I had more resources for T1's when I first started Paleo!

The real danger in Ketoacidosis is the insanely high glucose levels, not the ketones. The glucose can kill you - whether or not you're burning ketones.

In a low carb induced ketosis, with normal blood glucose levels, there's no issue - whether it's paleo-low-carb or Bernstein or Atkins...

You can get too many carbs [too many for you, that is] eating a paleo diet, if you focus on higher carb items (fruit, anyone).

For diabetics (T1 or 2), the best diet is low carb - any low carb. [yes, I'm bold enough to say that on a paleo website] This way of eating introduces less glucose into the bloodstream, and therefore requires less correcting (insulin, metformin, etc...).

By adding paleo to low carb -- you get double benefits.

Add exercise... Many (most?) T2's can reverse the disease and complications entirely. Many while reducing or eliminating medications! They don't have a metformin deficency!

For T1's it's a little more complicated, as by definition, they don't produce insulin, should require MUCH LESS insulin -- and reverse many of the related effects (heart disease, high cholesterol/triglycerides, kidney damage, etc)... You have to read Bernstein and the law of small numbers.

As much as I love what I remember about a snickers bar (or even high sugar fruits)... how I feel for a week after is just not worth it - and neither are the long term health effects of eating regularly [too much for me, that is... ymmv].

I'm not a nutritionist or a doctor but here is my guess...ketosis sometimes happens for paleo folks that are very low carb but you can benefit from paleo lifestyle without being in ketosis. I think that's about 50-100 carbs a day range in the form of veggies and maybe some fruit if you can tolerate it. Whole30 is a fantastic protocol. I'd focus less on ketosis and more on eliminating bad food and finding good food. Here's a great story http://wholefamilystrong.com/2011/11/01/diabetes-praise-report-2/