Assalamu-alaikum akhee,
Im really sorry to hear this.
I pray that Allah lightens her load and grants her (and yourself) the strength to bear this trial with patience.
Ameen.
You had mentioned in a previous post that she is receiving chemotherapy - so I assume that she is currently under the care of an oncology team.
Perhaps you can ask her doctor whether she would benefit from a procedure called 'pleurodesis' - which involves a chest drain being inserted, and a substance (usually Bleomycin) is injected (via the drain) into the space between the lung and the chest wall.
Insha Allah, this would ensure that the fluid does not re-accumalate - so that she would not need repeat lung drainage, and it may help with her shortness of breathe as well.
(If you wish to read more about this procedure, before asking her doctor - you can refer here:
http://www.cancerresearchuk.org/cancer-help/about-cancer/cancer-questions/pleurodesis-treatment)
Allah (subhanawataála) is the closest, to all His servants who are afflicted by disease.
So, dont lose hope in His mercy.
Let this affliction be the means of you both drawing ever close to Allah......for this is all that He desires when He tests the ummah of Nabi (sallalahu alaihi wasalam).
Our duaas are with you and your wife during this difficult time.
:wa: