My 5 1/2 year old son

Hi, I have a 5 1/2 year old son who was born three weeks early and has had therapy on and off since he was born due to Hypotonia and Coordination Disorder. He has had fevers on and off since he was 2 1/2 years old. It started around the time he was 2 1/2 when he woke up from a nap and was dragging his legs. He had to hold on to the wall for balance and would walk dragging his legs. We had all sorts of MRI's and blood tests and everything was normal. His SED rate was a bit elevated but eventually it came down. His legs got better in about five days. Since then we have seen many specialists and he has many tests done but everything is normal. The "leg issue" only happened twice but the fevers continued. We had about a 6 month window of barely any fevers and now they are back. They have come every two weeks for the last 6 weeks. The last time I took him to the pediatrician and he told me that it was PFAPA as my son had a canker sore in his mouth and he told me to just "suck it up"(in a nicer way) and accept it. The tough part for me is that my "mom instinct" cannot accept this as being enough. Even though he is in kindergarten its not great that he is missing so much school. He sometimes has the canker sores and will sometimes have toileting accidents along with bad breath. Those are the three most common symptoms. So, I am at a loss and wondered if anyone else may have any insight. He has been seen my Infections Disease doctors at Georgetown Univ. Hospital in DC and was not accepted by NIH in 2007. One of the docs from Hopkins wants to see him but he can only see him on the clinic days and with a fever. Of course, the last four fevers have been Friday to Monday. BTW, his fevers are low, usually between 101 and 102. When he was younger they were much higher. Thank you for giving me this opportunity to "vent".