Thanks for your query
Look TB is not always detected by the tests your mom has gone through. Even then Anti-tubercular drugs (ATD) should be started if there is strong clinical suspicion or strong radiological suspicion. Your doctor probably did the right thing though chest x-ray is not available here. But as your doctor took this decision after viewing that x-ray, i think your doctor has done right thing. As ATDs are already started it is no way to stop it until a 2nd diagnosis is established. Because stoppage of these drugs may cause drug resistance
which will be problematic if ATD is to be started again in near future. So please do continue the drugs and obviously you may take a second opinion
from another TB specialist in this regard.