Hi memoo.
Think i might be able to explain a bit to you.
Everything you describe about her blood gasses sounds like she is in respiratory failure.
If this is due to infection, it may be treateable but this is very dependant on the severity of her underlying lung problems.
If her poor blood gasses are due to the fact that she is end stage repiratory failure due to chronic chest problems with infection on top, then the outcome of this is not good, im sorry.
They will weigh up the severity of her condition and will discuss where to go from here with your poor mil.
Choices may be:
To treat with oxugen, antibiotics and physio.
They may offer intensive care or high dependancy care, this is by no means a decision taken lightly as the implications to end of life care are very serious.
They may offer to just allow her to slip away with comfort measures as there is nothing further that they can offer.
She sounds very unwell indeed and the fact that she has been in for 8 weeks is also a very bad omen as she is likely to aquire infection by hospitalisation.
So sorry you feel so helpless, if there is any way that you can get there to have things explained to you then go. Can i also add that in defence of what the hospital are telling your family, they may only take in a small amount of info at a time..this is normal and when they throw the confusion and complex nature of blood gasses, again it makes it difficult to absorb what is important.
This info just tends to muddy the water somewhat imhe
All the best my lovely, i hope that you get some explanations soon.