If you are truly worried, you can take him to a local urgent care clinic. They take walk-ins without needing an appointment. You can give Tylenol, then Motrin in 3 hours, then Tylenol again in 3 hours and keep on repeating this pattern until the fever comes down.
But, as a doctor myself, I would say that you need to get another doctor! There should never be a situation in which there is no one on call to give advice in an urgent situation, or even one in which you are very worried. All responsible doctors have a system in which someone covers for him/her when they are not available.
L.