A well-formulated ketogenic diet should indeed help your husband. The key to raising HDL is to consume saturated fat, so fatty meats, cooked in butter, will give him plenty of saturated fat to get his lipids in better shape, plus monounsaturated fat for energy.
You may be surprised to learn that the idea that elevated cholesterol puts us at risk of heart disease is actually not backed up by any scientific evidence. In fact there are several studies that seem to indicate that higher levels of LDL associate with lower risk of heart disease, especially as we get older. So your husband may not be at such great risk as his LDL number might appear to indicate.
However, the ratio of triglycerides to HDL does appear to be a good indicator of heart disease risk, and a ratio of 2.0 or lower seems to associate with the lowest risk of heart disease. To put it bluntly, your husband’s trig/HDL ratio is very high, which would seem to indicate a problem. Of course, the most direct assessment of heart disease risk is a CAC—a scan of calcium in the arteries. If your insurance would cover the cost, it might be worth trying to get your doctor to order this test.
In any case, lowering your husband’s carbohydrate intake to 20 g/day or less will not hurt him and may help quite a bit. He doesn’t need to increase his protein, but he will need to replace the missing calories from carbohydrate with calories from fat. Try to avoid polyunsaturated fats, especially from vegetable oils, and concentrate on giving him saturated and monounsaturated fat from butter, lard, tallow, bacon grease, and so forth. It may take some time for your husband’s blood work to stabilize once he starts a ketogenic diet. Give it at least six months before any further testing. Fat is tasty and satisfying, as well as rich in calories, so your husband may actually find himself more satisfied while eating less.
In the meantime, you might want to check out www.cholesterolcode.com, which is a site run by a software engineer who has been learning some fascinating things about cholesterol and its purpose in the body. If you can cope with the science, it should provide you and your husband with some very useful information about his situation.