Problem is that you cannot change someone's faith just like that, especially death, because the time of someone's death is very decided, and burnt in their faith.
Only the Gods could modify your uncle's faith so drastically, but it's not something the Gods do just for anyone.
You can ask Valefor now to help him, in case he is not meant to die right now, Valefor can help him heal.
But doing such a spell is pointless, especially because you are lacking time. In case he dies, you can do Anubis's / Satan's ritual and ask them to protect him in the afterlife.
Whatever happens, don't worry.
You're right and correct about the above , but one thing is like you already said is , even if it's someone time , the God's can change it, if important enough but this is very complex, for us to even understand but I have seen God's doing it, yea , myself even personally I think I've been meant to die 3 times [not willingly] and somehow miraculously always escaped death. Even when I done it on my self wishing to die taking so much stuff to just die then I was crying like a lil bitch for my own very life and I was entirely fucked and lost and depressed and so on so forth, THEY did helped me, changed my life and put me in the right direction , for the better!
@AFODO I know I'm probably going to fail, but I have to try. Otherwise, I wouldn't be able to look myself in the mirror after. So I will do Valefor's ritual everyday, then the day before the surgery, I will try to enter in communication with him. I still need to read about astral communication, because I never tried it before, but I say it again : The important for me is to try.
I never say this to anyone but when someone is a brother and I think this is a must and important then I am saying it straight to you.
STOP THINKING LIKE THAT! Release yourself of all doubt , regardless of how this whole situation end's up and truly would be best to have good faith upon the positive outcome instead of being pessimistic and less energic about it.
The best plan I see for this whole situation of yours and I wish you all of the best my brother is this:
1.
https://satanisgod.org/Ritual.html do this ritual , this is straight to Father Satan and the God's and the power of Hell , this is also very beneficial for anyone , regardless of how long you been a SS for but mostly for the one's who are new and at their start up point, the God's see that we want to get better and they believe you would be able to "pay back" in another let's say whatever time , meaning they Understand that you are willing to develop and also see potential in you , therefore They did helped me a lot when I could not help myself , in many very cases.
2. After you've done the ritual, try to connect with Father Satan , ask Him for his help and support
3.You could also do another ritual to a single God in Specific and do a deal with him , I have done both number 1 and 3 [this one] when I really needed it, just to make extremely sure that I am in the best way possible safe and successfully.
Now once you've done the above you could then use some runes,mantras to summon energy and direct it into your uncle, making an affirmation to heal him in the best way possible for him , this energy would work to boost his body,soul,mind[everything] into healing himself. Also , not only vibration but also when he's sleeping and even awake being you could breath energy into him from the Sun or just breath/absorb energy onto him with specific affirmation , this will empower the healing.
FINAL
Brother, I truly wish you well and the best to you and your uncle but you got to understand this, regardless of what is happening and of how this is going to end, you have to understand some things are fated to happen , change the course of a few things would not be as beneficial as you/me might think. Example , If the God's would have helped me saving my grandfather who raised me from death on that very moment while I was holding his hand on his final ends, then I would never have the power and knowledge which I posses now.
Although in the end it was a shock with my grandfather dying and marked me for a long time , I have developed ways to communicate with my Grandfather and making sure He is surely right out there and He was. Have faith and also be open to the learning of life , not all bad things are as bad as we think same goes for the good ones. This in itself it's a process , we are just living in this very system of the Universe , only difference is that we are not mindless sheeps without will and individuality but we're also having the GRATEST God's, giving us the privilege to be more then we could ever dream possible. So let's say if you uncle dies , then you should realize that one day you would be able to see him again and help him, the sooner the better but it's up to each own very being to help themselves , we do only what we can do when it comes to other. 
![Power of Justice [JG]](/data/avatars/m/21/21556.jpg?1705626106){kind=avatar}
