Hey Helen
Really hope your tummy settles down. I know exactly how you felt in the car. That was me on thurs and Friday. It's awful when you're in public too. Hope it passes soon.
Re your friend, Sounds like you're doing everything you can and it is now down to her. We can all make excuses that our lives are too busy but actually you can make so many quick meals. Whilst more expensive you can get pre prepared roast chicken and then could put it with microwave cooked veg (3mins) and microwave sweet potato (few mins). Or she can have pre prepared salads, use tin soup as a hexb, pre made sushi, could make a quick sandwich and then prepacked fruit. At the end of the day if you want to succeed you'll find a way to. I know that the last year my brain wasn't fully in it hence I put on weight. Depending on how much you want to help her could you meet up once a week and cook a few meals together then you can take half home, she takes half home and she has a few meals in freezer?
Hope you have a good day x