https://www.chameleonforums.com/care/caresheets/veiled/
https://www.chameleonforums.com/care/food/
https://www.chameleonforums.com/care/water/
https://www.chameleonforums.com/care/enclosures/
https://www.chameleonforums.com/care/lighting/
Read through these articles. You need to make some drastic changes to your care if this guy is going to survive. Education is the best tool to have when caring for these creatures.
First, nutrition:
Chameleons need to be fed as much as they can eat in about 5 minutes. At that age, he should be eating close to 15 crickets per day. Feed during the first half of the day since they need time to bask in order to digest properly.
Second, Supplements:
He NEEDS atleast 3 typles of supplements.
- Phosphorous free plain Calcium powder should be used lightly during every feeding.
- Calcium with Vitamin D3 which should be used lightly at most twice per month.
- Multivitamin powder which is used lightly twice per month.
These are extremely important for you chameleons overall health, especially his bone health.
Third, Lighting:
Proper heat and UVB lighting is required. A basking bulb that outputs the proper temperature is needed so the chameleon can warm up, boost digestion and metabolism.
UVB is needed to allow the chameleon to create and use Vitamin D3. Chameleons produce their own D3 out in the wild under the bright, strong sun. In captivity, they dont always have access to the suns unfiltered light so we use UVB bulbs to simulate the UVB radiation from the sun. Unfortunately, these bulbs are not strong enough which is why we supplement D3 into their diet.
Unfortunately, MBD cannot be cured but it can be stopped from progressing further.
I recommend seeing a vet with chameleon experience and making these changes that I, along with the members above, have suggested. Read the articles I posted. Take your time so you understand each section and dont be afraid to ask questions. We are here to help you and your chameleon out