Praise be to Allah, the Lord of the World; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Imam Ahmad and Tirmizi reported from Al Miqdad Ibn Maade Karib that he said: "I heard the Prophet saying: "Nobody has filled any receptacle worse than his own stomach. Indeed, it is enough for the person to eat that which is needed to strengthen his body. But if the person wants desperately to add to that then he fills a third (of his stomach) with food a third with drink and leaves out a third for his breathe".
Ibn Rajab said: 'This Hadith is a basic in the fundamentals of medicine". Ibn Massawaihi (a doctor) said: "If people applied the meaning of this Hadith in their lives, they would escape many illnesses and diseases and many pharmacies and shops would be cancelled'. He said that because the origin of most diseases is overeating. The doctor Al Harith Ibn Kildah said: 'The diet is the origin of health and the greediness of overeating is the origin of illnesses'.
So, there is no harm of making a diet for this blind boy. But take care of the following:
1. Do not tighten this program too much.
2. Follow a step by step progression in applying it.
3. Try to convince him of the usefulness of this program as far as health and intellect are concerned.
4. If you notice that this program has a bad effect on his behaviour or his thinking then it is better to give it up.
Allah knows best.