All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
It was narrated on the authority of Usaamah ibn Shareek that the Prophet, sallallaahu ‘alayhi wa sallam, commanded Muslims to seek treatment because Allaah the Almighty has not created any disease without appointing a remedy for it, with the exception of one disease - old age. [Ahmad and At-Tirmithi]
Therefore, what you should do is continue to treat your wife and be patient, because Allaah the Almighty promised that He will answer whoever supplicates to Him. Allaah the Almighty Says (what means):
We thank Allaah the Almighty that you are a believer in what was mentioned in the Quran and the Sunnah.
Finally, we supplicate to Allaah the Almighty to cure your wife soon.
Allaah Knows best.