Good catch Sally. I should have thought of DG considering his out of whack diabetic state.
Liquid meals like ensure or other as recommended by doctor may help.
Really please see your husband's doctor for advice, as his condition is very severe.
Agree to all waverider says.
The stomach problems are likely due to nerve damage from the diabetes. This is called diabetic gastroparesis. There are some medications that may help.
In addition it would be critical to get his blood sugar well controlled.
"Everything he eats makes him sick."
He needs to be evaluated by a doctor for an intestinal infection. Also, he should stop eating all the garbage, drop out the processed man-made packaged/canned foods. He needs to go back to a healthy diet of whole foods, fresh vegetables & fruits. Whole grains which you actually cook yourself. Very often when everything you eat makes you sick it's a telltale sign that there is either an infection and/or are aggravating foods in your diet which have only progressed as you haven't changed your ways.