How can you eat right if you cannot eat right? Where could I ask?

Background: My husband has ptsd and insominia, gained a lot of weight, now BMI 25, a good husband, works hard, cleans up after himself, helps with the kids, often tired after a long day at work, snacks in the evening, problems eating in the morning, very unhappy with weight gain, works out a lot but does not loose weight, does therapy, took yoga classes, still practicing yoga and muscle relaxation after Jacobson

So my has been told that he needed to change his diet by a physician. He is mostly healthy but he has been told it will have negative consequences in the long run. His diet is not good, see my other thread for examples.

I talked to other people with ptsd and spouses of people with ptsd. They told me that it is just so difficult to eat right if you have ptsd.

He has the biggest problems in the morning, has nightmares and insomnia and often wakes up feeling lousy. Typically has an energy drink or coffee than as well as some chocolate. Also cake/cupcake, pralines (without alcohol), ice-cream, sometimes banana or a tangerine.

A lot of people have told me to leave him alone, because how heißt eating is just a symptom and cannot be changed. Really? How can he eat better? Where could I ask?

Sorry for having two threads about similar topics.