There are tons of information on diabetes on the internet. You will be sorting this out for weeks. Take it a day at a time and keep learning. I liked "Blood Sugar 101: What They Don't Tell You about Diabetes."
No one knows why diabetes happens. You may read that for type II, it is triggered with risk factors of weight gain and physical inactivity, but in reality, the researchers do not really know why it happens. Ditto for type I, "pancreas shutting down." Whatever type your husband has, it is definitely not due to something he did or failed to do.
The weight loss is happening because his body cells are not getting the energy (glucose) that they need. Insulin from the pancreas is needed to transport glucose into the body cells and if this is not happening, then it is as if the body cells are starving. More fat is burned off trying to create more energy, hence the weight loss.
We hope you find this general health information helpful. Please note however, that this Q&A is meant to support not replace the professional medical advice you receive from your doctor. No information in the Answers above is intended to diagnose or treat any condition. The views expressed in the Answers above belong to the individuals who posted them and do not necessarily reflect the views of Remedy Health Media. Remedy Health Media does not review or edit content posted by our community members, but reserves the right to remove any material it deems inappropriate.