is completely curable in most cases.
The main issue is non-compliance - many may discontinue the drugs, 'because, they have no symptoms'
The problem is at times from associated conditions - like Immune deficiency
, cancer chemotherapy
and the like.
Very rarely multi-drug resistant cases occur - MDR-TB - even for that, there are specialised centres with special facilities for culture, drug sensitivity testing and treatment tailored to the particular instance.
Your friend is(?!) obviously on the path of recovery She will recover.
She can marry. She will be like anybody else - no one may know! - she herself may forget!
She has to finish the complete course of the treatment. - her doctor will advice - he will do follow up x-rays, blood tests etc
Just one more thing - you say she is now taking 'one tablet' - the tablet may be one but the medicine is never one - always a combination is given to prevent resistance. Check it up