Salad can be a good solution for my mother who wants to reduce her weight?

Depends how she eats it. My sister loads it up with cheese and ranch dressing and doesn't understand why it's not working.

Yes, but make sure she gets some protein as well, and a good exercise routine.

Vegetables, meet and fruits.

Yes. Salad, other vegetables, lots of fruit. She could still eat meat, but fresh lean meat, cooked, and not processed. Fish is also a good source of nutrition, except fried fish. Grains and fiber are good, stay away from bread, though, especially white bread.

Also she should exercise.