Why does he get treated this way?

This is about my cousin, he is 20. This started when he was 3(that is when he told me he remembers it starting). I have personally seen my uncle hurt him a few years ago on a holiday. He got beat with belts(really hard, he has sent me pictures of his wounds when this was happening to him) from age 3 to age 18 it happened to him. He never got to finish high school, his parents took him out of school in the beginning of 10th grade, to start him on online school, but they never followed through with that, he said they claimed they couldn't afford it so he just had to stop doing school all together. He has tried getting help for the abuse at 17-18 when he was in this group for high schoolers at this church he would just walk to(right by his house), his group leaders would egg him on, saying he could speak to them whenever he needed to, except that was a lie. He has walked places to meet up with them before(when they would invite him) but they never showed up, when he needed someone the most. He stopped going last year at 19. Ever since then he has kept to himself, right now my aunt and uncle just yell cuss and put him down daily he said. He has no way of leaving, his parents tell others he is 4 years younger than he really is. They get away with this because my cousin doesn't look his age, he has no ID his parents never allowed him to get one, and his parents lost his birth certificate when they moved when he was 13. Why would his parents treat him like this from age 3 to age 18? Is this normal? Those times he was supposed to meet the church leaders to talk, I went with him when they never showed up. They never contacted him when he tried calling to ask where they were, and they never apologized to him for not showing up. He told me they replied back to him a week after that, just saying they couldn't meet up then even though they had planned that day to. This happened over 10 times to him, I know because I went with all of those times.

ok a bit strange saying they couldnt afford school since here in america public school and many online schools are free for pre school through 12th grade (in other words until a person turns 18 and graduates high school.) even some adult schooling like the GED (like a high school diploma) in some locations are free.

Also he is an adult so all he needs to do is contact his locations county health department and request a copy of his birth certificate if I remember right the first request sometimes can be free, but if there is a fee for it, its only 10 bucks.

he can also contact adult protective services if he is an adult. they will come to him and if he really wants to leave his parents home they will help him, they will even help him get the a copy of his birth certificate and help him go to school to get his high school diploma if he wants to. if it turns out he is not the age he says he is and is the age that his parents say he is, (Im assuming you are not old enough to know the month, day and year this person was born from actually being there at his birth, and sometimes teen agers lie about their age so assuming there is a question in him about his age) adult protective services can refer the case to child protective services and if things are as bad as you posted for him and not his making things up they will remove him from his parents and place him in a foster home.

Also since you are located here in the USA if you feel this is abusive and wrong you can also call child protective services\ adult protective services and the police and 911 and other government agencies that every state and major and sometimes even small towns in the USA have, and make a report of abuse. you dont need to use your name. you can just say I want to make an anonymous report of abuse. then the police and social services will investigate right down to contacting the department of health to verify the guys age and the abuse allegations.

my suggestion if this continues to bother you call the police and protective services. other wise all you can do is let him handle it as he sees fit.