spreads through infected water/food.
The most important precaution you need to take is to drink filtered water, eat freshly prepared food to avoid recurrence.
Regarding diet there should be no restriction except to avoid spicy/oily food as sometimes it can cause gastritis
Regarding antibiotics, once you complete full course, there is no need to take repeated courses.
Regarding bed rest
she need not take absolute bed rest. If she is feeling OK, she can continue household activities. If she is feeling weak, she can take rest as long as she recovers fully.
Hope this has solved your queries.
Wish her good health & speedy recovery.