Best you consult an Orthodontist at this stage.

Regarding the protocol of cleft lip and palate surgery. Treatment starts the day baby is born with cleft lip and palate. It's called nasoalveolar moulding. When the baby is 3 month lip surgery (cheiloplasty) is done. 8 month to 1 yr palatoplasty..when the baby is 2 yr old, Speach assessment is done. 9 to ten yr when it's age for canine to erupt orthodontic treatment followed by alveolar bone grafting should be done. if required lip revision and till 17 year  secondary corrective surgery can be performed like secondary palatoplasty. Jaw corrective surgery(orthognathic surgery)  can be performed after 17 yrs.  My suggestion is go to any center whr cleft lip and palate is performed and get evaluation done. These centers are funded by NGO'S and any surgery will be performed free of cost. It's not that if they are doing it for free treatment is bad. The surgery and treatment is as good as any other corporate hospitals.

age; ideal step 1;get x rays done step 2; visit an orthodontist specialist who specializes in cleft lip and palate step 3; should also visit oral surgeon who specializes in orthognathic surgery step 4; after getting consultation from both above specialists, you can decide the best course of action

Would suggest an Interdisciplinary approach towards his treatment. 12 years is ideal to get Orthodontic correction(if required). Visit a a Pediatric dentist and also get a Orthodontist opinion. A detailed clinical and radiographic examination(opg & lateral ceph) will determine the step by step approach towards management of lower jaw prognathism.