Oxygen chamber for Autism Treatment?

My sister has a 4 year old son who is Autistic, and she has recently told me that she will be bringing him for oxygen treatments. The woman who does the procedure has her detoxing her son, taking various minerals and weaning him on to a gluten free, casein free diet. I am looking for anyone who has had a personal experience with this procedure, wondering what your experience has been (good or bad). The treatments are very expensive and I am concerned that she may be spending her money looking for a result that is not possible with this treatment. I have never heard of it, know very little about it, and don't want to search the internet, and it's abundances of misinformation. Thank you for any responses :)