Baby neurology

Hello,

My son is 8 month old. He was born at 37+ weeks. He is a twin so his birth wait was low. He did not have any problem in the hospital and was released home with mommy.  For the fist few months he acted inadequate. He was very colicky and extremely tense. The doctor felt that the reason is milk intolerance, but he was gaining wait normally (he is breastfeed 80% and formula feed 20%)  We change the formula and put mommy on milk/soy free diet. It did not help. He is still very colicky and stiff. He started daycare at 6 month. The daycare nurses found his stiffness right away. They have never seen the baby that stiff. I took him to neurologist.
Based on ultrasound my son was diagnosed with benign external excessive spinal fluid. Unfortunately it did not explain his stiffness and inability to relax. Even when he is falling asleep his legs are still moving. It takes at least 4 hrs to put him asleep at night even when he is very tiered. It looks like he cannot relax. He constantly tosses and turns. My son is extremely active and restless. He compelled to jump, crawl or roll even when he is visibly tired.  He also constantly rubs his hands. We also noticed that back and top of his head are very warm, whereas the forehead has normal temperature.

Any idea what cases this behavior? What can I do to help? Please help.