Introducing Self

I need menu and food ideas, my brain is overwhelmed, lol.
Long story short, I am a live in aide for a family. There is a husband and wife team, she is 67, she is 65. She is a severe diabetic, has had numerous heart attacks, a few strokes, and a few other health problems. The husband actually is in good health, takes care of himself, etc. The wife has a brother that lives with us, he too is severe diabetic, has had a couple of heart attacks, but fortunately no strokes.
I cook, clean, take care of all health needs, and any thing else in the home that needs to be taken care of.
Here is my problem, all of them are super picky eaters, and not a single one of them likes what the other likes, except for a few things. I have to practically cook three, or at the least two meals per night.
Jo (the wife) loves chicken, but neither her brother or husband will touch it. Oak (the husband) likes steak, but the other two don’t. Jo and Oak love tacos/taco salad, but her brother doesn’t.
About the only foods I can get any of them to agree on is meatloaf, ham and beans, chili, hamburgers, beef stroganoff, spaghetti, potato salad,salsbury steak, chicken and noodles (amazingly enough!), and pretty much anything else with noodles.
I wouldn’t mind having to repeat things, but that gets blah after awhile. Sometimes I am able to make like just two meats, lets say baked chicken, steak, and then about two sides, some type of carb, and a veggie. Marvin (the brother) is the one who is super picky, I can hardly find a protein (meat) he will eat. No chicken, ham, beef, pork, nothing. The only things I have found so far are hotdogs, hamburgers (or hamburger mixed in something) peanut butter, and eggs.
I feel like a mother of a picky three year old who will only eat pbj sandwiches, lol. ARRRGHHHHHHHH!!!
Thanks for letting me vent!!