I don't have a lot of time to cook either, and honestly, I don't WANT to spend my free time cooking! I am such a big fan of making tasty salads. I buy tons of organic spring mix and use it every day, usually for both lunch and dinner, with my meals. I buy organic because it's good and fresh, and it also lasts longer. A large container is about $5 and is plenty for my husband and I to share for a week.
For a good lunch, I like to cover a plate with salad, top with a little bit of a light dressing (I go for a vinaigrette-type dressing or something olive oil based) and then I top it with some grilled chicken. I love to add in extras that I enjoy, like a little bit of avocado and lots of grape tomatoes. Sometimes I throw some baby carrots in there. I like to add different things depending on my mood. If I feel like I need some grains, I use a healthy pita (I use sprouted grain, but whole wheat is another option) and stuff it with the salad and some kind of lean meat. It's also easy for me to pack this for work. I just stuff a ziploc bag or container with the salad and take a piece of chicken too.
I usually have protein bars around for when I need something quick and easy. Sometimes there just isn't time to buy food or prepare anything, so these are a good option for me. Sure they might not be 100% natural (you CAN find some that are though!), but it's way better than picking up a fast food breakfast or donuts or something. To me, they taste like a treat and give me some vitamins and protein.
I definitely think your husband can try his best to make small changes here and there. Simple swaps, like sodas for water, white breads for whole wheat, adding in more fruits and veggies (by the way, apples are great to take on the go!), it all makes a difference. As for exercise, little bits here and there are good too. When I travel for work, I usually go jogging outdoors around the hotel areas, or I look online to see if they will have a gym. It's good to get out and take a break and burn off some stress from work! I also unfortunately have to sit a lot at work, but if I have a lunch break, I like to go walking outside to get some fresh air and get away from the fluorescent lighting. As for the driving, I wouldn't worry about that! I drive everywhere since I don't work near my home, and honestly I don't always feel safe as a young woman walking by myself, but I don't feel that it hurts my fitness. I just do my driving and squeeze in exercise when I can