Can you help us heal Sid?

I'm helping to treat Sid the injured cat, he has been straying for 2 years after we think his owner died. He was found badly hurt today so I got him to the vets who discovered he had a nasty break in his foot. Sadly he also tested positive for feline leukaemia. We want to give him a chance as he is friendly and tolerated being examined whilst I held him today. I'm working in conjunction with Tenderpaws rescue as he needs expert care. He is now safe with them tonight but will require lots of treatment and may loose the leg if it doesn't heal. We didn't want to give up on him today but need your help to find his treatment. After so long surviving outside he deserves a chance. He's an entire male with no chip and despite posters being shared since February no owner has been found so we can only assume the information received about his owner being deceased is correct.