he used to be 240lbs now is 105%26 looks like he's on his death bed
Well without knowing more about the situation, it sounds like there's something else wrong. Typically diabetics and people that are allergic to gluten wouldn't just drop over 100lbs for no reason.That being said, weight gain happens when you take in more calories than you are burning, so increasing the number of calories and good fats (nuts, olive oil, avocados, etc) should bring the weight up.To build muscle you'll need to increase protein intake from eggs, lean meats and combining beans %26 rice.Of course you'll probably want to make these changes in conjunction with your doctor, but there shouldn't be an issue with either health issue in doing this. I would suggest mild cardio workouts while the weight is low.Once the weight comes up to a healthy one, then and only then, would I begin to exercise for muscle building, lifting weights and doing more strenuous exercise.
Is he following his diabetic and gluten free diet? Is he allergic to gluten or does he have Celiac Disease? there is a difference.
If he's recently diagnosed and just starting the gluten free/diabetic diet, it will take time. Honestly 240 is too big! He needs to see his doc for his healthy weight and BMI. If he has Celiac Disease, it takes tiem for the body to heal from the damage of gluten and it will even out in time.
Hope that helps.