My favorite breakfast on the go is Banana Oat Muffins. They are sweet, but not overly sugary like a donut, and the whole grains will keep you full longer. Put extras in the freezer.
Banana Oat Muffins Recipe :http://martasrecipes.blogspot.com/2008/09/banana-oat-muff...
Though the sausage biscuit has protein, sausage is so full of fat and filler that I would not recommend it as healthier. Besides the biscuits are all white flour and that turns to fat quickly in your system.
A breakfast burrito is a good idea, make them up in whole wheat wraps, put in black beans, scrambled eggs, cheese, saute`d peppers & onions, salsa, and all he has to do is microwave it. Make a dozen and store in the fridge short term and the freezer long term.
Make some whole grain waffles to freeze, he can heat like eggo waffles. A little Peanut butter and fresh fruit or syrup.
You are right that the donut is not healthy. The best choice from work is the oatmeal and fruit, complex carbohydrates and protein in the oatmeal, lots of fiber - that keeps you full longer. This is what I eat every morning, a whole grain bread or hot cereal, 3 fruits and a handful of nuts - keeps me full until lunch!