I'm so happy for you that you finally know what you are dealing with. Funny, I am from Long Island too, grew up here and still live here but plan on moving soon. I also have been to most of the beaches here including Fire Island, played in the woods as a little girl, walked through marshes, you name it! I was a real tomboy!
The only advice I can give to you is to start reading books about chronic lyme. I became better using alternative medicine and have been in remission for 4 years now. My brain was affected, darn, my entire body was affected from lyme, there was a long period where I lost the use of my legs and had to use crutches or I would fall straight down.
The book that helped me the most was Dr. Jernigan's "Beating Lyme Disease Using Alternative Medicine" and I believe you have nothing to lose by reading it... You know what they say: knowledge is power...
Good luck to you and your Dad!