Hi My Son He Is 4 Year Old And Dignosed

Hi my son he is 4 year old and dignosed for autism .he dignosed for high function . His speech is less. He is taking ABA and speech theropy too.he is not potty trained yet. I tried GFCF diet for six month . But it didn't work . He was tired all time like he has no energy and had diarrhea .and he was doing potty 3 times a day .it wasn't like potty it was gooey .then I stopped . Now he is taking regular homemade food but doing ball moment next day . U know on the Internet lot of things for curing autism . But I'm just giving him Vita Spectrum vitamins and minerals powder. And Nordic natural DHA for children. R these medicines reliable? And is GFCF diet is 100 perscent work for autism recovery? And which medicines r really helpfull for my kid condition . and especially in his speech . He has full eye contact . Hearing ,smelling ,touching , looking every senses r perfect he looks perfect . Just his speech and little bit behavior . If he is stuck in one thing so mostly he takes 5 or 4 minutes to come out from that situation . If u guide me best medicines and best diet for him so I will be v v great full for u . Thank you