It’s always nice to combine both nutrition and exercise into a weight loss program whenever possible, but that doesn’t mean you can’t lose the weight if exercise isn’t an option. In fact, the largest percentage of weight loss is a result of a well-structured diet. Yes, exercise will give you an added benefit of burning calories and building muscle, but it doesn’t compare to what can be achieved through proper nutrition. Given your symptoms and limitations that occur with the neuropathy, I would focus on your nutrition first and perhaps incorporate some beginner resistance training, using bands while in a seated position. You may want to speak with your doctor about your options and perhaps he can refer you to a registered dietitian. It is possible that as you lose weight you may find improvement in your medical condition which will allow you more exercise options down the road.
Best of luck to you!