Autism-3 yr old son with PDD-NOS

My son was diagnosed with PDD-NOS at age 2. He never babbled and is non verbal. He is 3.9 and has just started to say words like duck, cat, car, truck. He has heavy metals like lead, etc. He is allergic to whole egg, sunflower and is GFCF for the past 7 months. His skin is fair, hair is thick. He likes to suck his thumb, hold his favorite blanky and smell me and my clothes. He has had all his vaccinationsI including flu shots, up until he was diagnosed on the spectrum. He is usally happy, but has visual stims, hyper like running around house and jumping on couches. He drags or pushes his body on the floor and likes to line items up/together. He is good with puzzles and is a problem solver. He can put letters together (puzzle) from A-Z, but can't say any of the letters. His maternal grandmother has diabetes and his paternal grandmother died, she had diabetes. My son also have twin brothers that are develpmentally delayed. Often my son does not sleep through the night. Currently he is on MB-12 shots, cod liver oil, probiotics and multimineral vitamins, but the last two items I am slowly stopping because if he suspects I put any supplements in his food, he will no longer eat it. We currently see a DAN doctor and were going to start chelating lead, but we would like to go the safe and natural way to recover him from Autism. Thank you for info you can share with me.
Leah Cim