Oh PMB you poor thing!

Ask for a referral to a pain management team/specialist - diclofenac and paracetamol are not even close to good enough! For the US readers this is Voltaren and Tylenol.

The treatment for TB interacts with a lot of other medications and it sounds a lot like your doctor is not confident enough to prescribe serious pain killers when your brother is also on TB medication. I agree with Christine, now is the time to make a fuss. Your brother should not be allowed to go through this on the most basic of pain medications and you need impress upon the doctor that current medications are not adequate. And don't let your brother underplay the pain he is in. Try and get him to agree that on this occasion, when he gets in front of the doctor, he should not be "brave". I remember after a hour of discussion at home with my Alex, we agreed that his pain was severe enough to warrant a request to escalate his pain medication to the next level. When the doctor asked how he was managing he replied that he could handle it... aarrggghhh!

I have come to the conclusion that this is something that men do, for no reason that I understand other than pain tolerance appears to be attached to sense of worth somehow

Is it possible your brother thinks that to admit to pain is a sign of weakness or failure? If so, maybe it would help if you reassure him that others in his position need something opiate based to even touch the pain. Some possible options to ask the doctor about are fentanyl, oxycodone, or morphine to see if any of these are available ?