Can you please help chunky

I got chunky as a puppy from the SPCA. He had a tumor and he was the last puppy left from the litter. Luckily the SPCA paid for the tumor removal. About 8 months later chunky had to have a cruciate ligament operation and got a metal plate put in his leg. He has never been the same. Unfortunately his leg isn't coping well. The insurance won't cover it as it's an existing damage. He may need to get it removed and I don't have the money. He is my best friend.