As Salamu 'Alaykum,
My young brother, I will certainly continue to pray for your father, Mahmood. What ever the outcome, know that it is Allah's Will. I am speaking from personal experience as a person who faced a similar situation when my terminally ill infant son was born. I tried to bargain with Allah. I thought I knew what was best for me and my family and I made lots of promises to perform this and that and the other things IF Allah would just let my son live. I am so ashamed of my behavior back then over thirty years ago. Who was I to make deals with Allah. Who was I to think that I knew what was best for the situation. As I grew in my Christian Faith, (I am a new revert to Islam) I took comfort always in The Bible verse,
Rom 8:28 And we know that all things work together for good to them that love God, to them who are the called according to his purpose.
الْقِدِّيسِينَ.
Rom 8:28 وَنَحْنُ نَعْلَمُ أَنَّ كُلَّ الأَشْيَاءِ تَعْمَلُ مَعاً لِلْخَيْرِ لِلَّذِينَ يُحِبُّونَ اللهَ الَّذِينَ هُمْ مَدْعُوُّونَ حَسَبَ
Allah Knows! Insha Allah, may your father recover fully. If he doesn't, find strength and comfort knowing that Allah knows all and knows what is best.
I will had your father, Mahmood, to my du'a.
Brother Frank.