Hi Jasmina, Your English is very good and we were happy to hear from you!
It is good to learn that you have found a way to get help for your son. You have made some good starts. I'm sorry not to be able to give you suggestions on amounts of supplements for detox but can say that the amount you are giving of B6 is quite low, nothing to be concerned about; (you can check with your doctor about using more). Some people need to take it with food to avoid stomach upset.
In addition to the approaches you are using I wanted to mention that it is important to avoid potential triggers that may be affecting him. Triggers include diet and also things in the environment. We have a book, Stop Your Tics by Learning What Trigger Them -- and it was just translated into Chinese. The concept is that if there is something aggravating his system, it is best if it can be avoided and this will also help other approaches be more beneficial.
The publisher gave me these two links for the book in case you are interested. I don't know how it works with you being in China and trying to order from Taiwan, but I hope this could be of some help to you (please let us know if you decide to do it):
FROM THE PUBLISHER:
You could find the complex Chinese edition on our official website:https://www.wunan.com.tw/bookdetail?NO=14327
Or on Books.com.tw:https://www.books.com.tw/products/0010820544 (Books.com.tw is the biggest online bookstore in Taiwan)
We are looking forward to hearing back from you, Jasmina and hope you can find all the answers your son needs, Sheila