I am really sorry to hear that you and your son are going through this. Your son is lucky to have a mom like you who treats the lyme story seriously because, unfortunately, lyme disease is a real disease. I've had lyme for many years, since I was in elementary school and there is no doubt: lyme has clearly slowed my growth and it has made it close to impossible for me to gain weight. My first symptoms were also neurological. I had trouble in school. Teachers were noticing that I had concentration problems. I just couldn't focus. Then the symptoms starting to add as the years passed.
I thought I had Lyme but it turned out that I had Lyme and Babesia (positive tests). I never took co-infections seriously but I should have. They can lead to treatment failure if you are treating only the Lyme. It's important to remember that, as with Lyme, tests for co-infections can be unreliable. Also, some of these co-infections not only complicate treatment but can cause serious symptoms. Babesia (a parasite), for example, although not as sophisticated as the Lyme organism, can have a very brutal effect on the body. It is notorious for causing anemia, in addition to other serious symptoms (severe headaches, etc).
It''s very important to get informed. This disease doesn't give you a choice because unfortunately, most doctors either know very little or haven't got a clue.
I hope you and your son get help and support. Having people around you who understand that this is a real disease is essential. Sadly, it seems that pretty much the only people who are not ignorant when it comes to this disease are the ones who have it.