Is it true that autism people are dairy tolerance or does dairy tolerance happens to anyone? does it affect anyone’s body ?

You need to read The Way I See It by Dr Temple Grandin. This is a book written about autism by a professor that has autism. She is a wonderful role model for anyone with autism. Go to school and walk through the door and make something of a future. Check out the movie Temple about her life.

It can happen to anyone. It does seem that people with autism have more food sensitivities that neurotypical people. But many people with autism don't have any issues with any food.

You need to slowly introduce dairy and gluten. Eat small amounts of 1 at a time. Your body needs to re learn how to digest them.

as long as you feel good, you can slowly increase the amount.

Why are you letting your dad choose what you eat and what kind of diet you follow? You're 22 years old, not TWO. You can and should be making  YOUR OWN choices as an ADULT, which is what you are. Part of your problem is that your dad doesn't want to let you GROW UP, which is what you need to do. It's insane that he makes these kinds of choices for you at your age. You should be in college (they call it university in the UK) by now, and getting ready to graduate and enter the workplace.

There is no dietary cure for Autism, because diet is NOT what causes the disorder. It's largely genetic- at least according to the researchers I know who work on it. I have mild Autism myself, but I don't lead the kind of life that you do. I live independently, work full time, drive my own car, own my own car, have and keep a horse, pay my own bills and taxes, and on and on. I've got a college degree and have been certified as a medical coder, too. That's work I love doing.

I'm not surprised you lost weight by going gluten and dairy free. By forcing you to do that, your dad was robbing you of an important source of protein and other nutrients, which in turn led to deficiencies in at least some of them. What he doesn't realize is that he may have set you up for a lifetime of health issues as a result. You should see your own MEDICAL doctor about this.

Nothing cures autism. You are born with it and will have it your entire life.

People with and without autism can have an intolerance to dairy and to gluten products. 

Being autistic doesn’t have anything to do with being intolerant to dairy. Any person can be intolerant of diary and gluten products. 

Go to a regular medical doctor. If you are intolerant to diary they can help you.   Also ask your doctor to explain your autism to you. Get some facts. 

The word is "intolerance". Many people have digestive problems with dairy and gluten. Many (me included) feel better when we eliminate these from our diets. Will it cure autism? I don't know. I doubt it. But you can try an elimination diet for a while and see if you feel better. Then try introducing things back into your diet and see if anything affects you. Eliminating gluten means no bread, no pasta, no pizza (although some places now have gluten free crusts, and no fried foods that have been dredged in flour. That can be hard on the typical diet in the US. But I avoid gluten, and I don't have too much trouble. There's usually something I can eat anywhere I go- meat, vegetables, salads. In a pinch, I eat the inside out of a burger or sandwich and don't eat the bread. 

It can happen to anyone. It does seem that people with autism have more food sensitivities that neurotypical people. But many people with autism don't have any issues with any food.

You need to slowly introduce dairy and gluten. Eat small amounts of 1 at a time. Your body needs to re learn how to digest them.

as long as you feel good, you can slowly increase the amount.

You were Scammed. Autism is a brain disorder, what foods you eat cannot affect the brain or your condition. There are No tablets which will help. So eat what you like and avoid her.