What's the prognosis for a arnold chiari malformation?

I have a 7 year old boy who had surgery almost 2 years ago for arnold chiari type 1 brain malformation. the surgery was a decompression. he also had a tethered spinal cord that was also fixed surgically at the same time. will he live a normal life, or can all this happen again? can his brain compress again? can his spinal cord tether again? he is going through so much, and i just want to know what the future could be for him. He just got diagnosed with childrens GERD recently, and today got diagnosed with torticollis. his neck muscles spasm and stiffen.they also think he has autism. he is a happy fun child, but it seems like the doctors keep diagnosing him with something new all the time. could this be from the surgeries?