Exercise is good for your health. However, if you can't exercise, you can still lose weight. Cutting down the number of calories you eat each day is the primary way to lose weight. There are also: bariatric surgery, fasting, being a Super Athlete, for example.

If you log the food that you eat in fitday, and you are truthful about portion sizes, you will see how many calories you eat each day. Then, make it a goal to reduce that number by say, 500 calories every day, and see how comfortable you feel with that. Try that for a week and look at the results at the scale. This should demonstrate how you lose weight without exercise.