Since he is only 2 years old he would probably tolerate the surgery and anestesia well. However,those things are always a risk to animals and even people. Your Vet is your best advisor because he knows your cats history and has seen his injury. No one wants their beloved pet to suffer and if the surgury will make his life better then he should have it. As far as the cost that varies among Vets. There are specific agencies that finance pet expenses
www.carecredit.com is one if you need help with the bill. I'm sure you will make the right decision as I can see that you love your cat very much.