Hi kerilee01, welcome to the board!
I am sorry your mother is sick. How long has she had symptoms? I believe the doctor you are asking about is an infectious disease doctor who does not believe in chroinc Lyme. I would not recommend him.
Does your mother live in CT? If you need a doctor recommendation, you can email me at email@example.com There is a Lyme doctor in CT who comes highly recommended.
bIt is also important to learn as much as possible. I recommend reading Dr. Joseph Burrascano's 2008 Diagnostic Hints and Treatment Guidelines For Lyme and Other Tick Borne Illnesses at http://www.ilads.org/lyme_disease/B_guidelines_12_17_08.pdf He is one of the top Lyme doctors in the country, and many Lyme doctors follow his protocols. He discusses antibiotics and doses starting on page 18. I also recommend the books "Everything You Need To Know about Lyme Disease Second Edition" by Karen Vanderhoof-Forschner and "The Lyme Disease Solution" by Kenneth B. Singleton M.D.
I hope your mother can see a knowledgeable doctor soon. She is lucky to have your support.