Get a delivery service - Tesco/Asda/whatever
Once a week order - just repeat the old one and adjust it a little so it takes all of 5-10 minutes.
Breakfast is cornflakes, milk, blueberries, bananas, eggs, toast.
Lunch is sandwiches - bread, butter, cucumber, ham/chicken slices, soup cans
Snacks - Biscuits, fruit - apples and pears
Dinner -
Pizza (ready ones from the store)
Pasta with jar of sauce and can of tuna
Baked beans on toast,
Grilled chicken/chicken nuggets (all frozen) with chips
Fish fingers, fancy fish (again frozen), chips
Mac and cheese.
Takeaway
Every day for dinner - cut a large plate of carrots, cucumbers, courgettes, mushrooms, radishes, celery, cherry tomatoes with homous/yogurt to dip and a packet of salad leaves.. and fruit.
You can get them started on carrot sticks and yogurt while the pizza/fish fingers etc is cooking.
Or take baby cucumbers and carrot sticks for the car as they are used to eating in the car (maybe with a packet of pitta bread).
After a few weeks you will know what gets eaten vs thrown away.
It's not proper home cooking - but it's a middle ground between cooking from scratch and takeaways every day.