My son who is 8 years old is having a lot of teeth problems. his teath is having decay and not coming properly. its like his teaths are getting eaten.

See a dentist asap!: It's sad and unfortunate that someone so young has so much dental decay. This is related to eating too many junk foods and liquids and poor oral hygiene. Please have him seen by a dentist as soon as possible to get all his teeth fixed and also ask the dentist to educate you and your son as how to prevent future cavities. Then be strong and enforce those good habits, avoiding the bad ones.

Habits or systemic?: Two culprits come to mind when i read your question. Your son may have a systemic disease that is causing his teeth to improperly develop or he has very poor oral hygiene habits and to much sugar intact. My suggestion is to seek out the care of a dentist who specializes in children- a pedodontist - and have that person properly diagnose the problem and than follow thru with care! good luck!