Vet expenses for my doggie.........

I have an 11 1/2 year old Shih Tzu named Oscar that needs surgery. He got an eye infection that turned into an ulcer on the eyeball and that has ruptured. There is nothing more to be done and the eye will rot unless I have it removed - at a cost of $2,400. The Vet says this is a very painful process for the eye to die. There is no way I can even come close to that amount - I am barely making it thru each month as a disabled senior on a fixed income. He has increasing pain and is on pain medication 24 hours a day. He still has bouts where he bobs his head (which has been in a cone for over a month) and cries for up to an hour - until the meds kick in. I try to give him the meds in a consistent way but it can come on fast before I know it. The bouts are increasing and I am having a hard time watching him suffer. I had decided to put him to sleep so he wouldn't hurt anymore but am rethinking that based on many loving suggestions I have received thru the social media site Next Door. I now want to try to raise the money for the surgery. I use Ahwatukee Animal Care on 48th and Elliot. They have been so good to him while I have been trying to treat him for this. Putting him to sleep was not what I really wanted to do and it's going to break my heart to lose him (I'm crying already) but I have to do what is best for him. If I could do the surgery instead that would be wonderful for us both. He's such a sweet doggo and I've had him since he was almost 1 year old. He was a foster fail. LOL I had agreed to foster him from a friend of a friend who could no longer keep him. I've been a dog rescuer and caretaker for many years and have experience in finding new homes. But my friends and I fell in love with Oscar pretty quickly and I decided to keep him. He's deaf but we soon developed a routine that helps with that - he knows hand signals for come and stay and if I need to get his attention when he's in a room, I flick the lights several times and he knows to come to me. It really has worked out for us and I got a second rescue dog to keep him company. They are wonderful together. But right now he is suffering and I need to find a fix for that.